Knee-Deep in the Dead
Start by looking to your left and going through a doorway to a staircase. To the right of the staircase is a pillar. Go to the right side of this pillar to find a button. Press the button and go back out to the room you started in. There will now be an open doorway leading outside, go through it.
Grab the blue armor pickup that is out here. Then take the only other doorway here to get to a hallway. Follow it to the end and interact with the dead end to open up the wall. Take a right here and go through the door, there will be an imp. Let him come to you and try to kill it such that it dies right under the door that opened up. Close the door on the corpse, or wait for the door to close and you will pop:
Unlocked by 1,377 tracked gamers (92% - TA Ratio = 1.04)
If you have trouble doing this with the imp (enemy 1/10), there will be a couple of zombiemen behind you to try it with. If you do not get it, do not worry, this achievement will most likely come naturally. Either way, kill the zombiemen (enemy 2/10).
Once that is done, continue straight through that door to the exit door, and flip the exit switch.
E1M2: Nuclear Power Plant
Take an immediate right and go through the door. Follow the stairs up, on the right is a zombieman and to the left is the red keycard. Go down the staircase that you did not take to get up here, and watch out for a zombieman at the bottom of the stairs. Go straight across the room and open the red keycard door. Follow this hallway through a room with acid to get to a dead end. When you reach this dead-end the platform will descend. There will be an imp and a zombieman, kill them.
When they are dead, grab the armor down here. At the other end of the room from where you came is a lever. Pull it and two doors to your left and right will open. Take the right door and follow the hall to the end and take a right down some stairs to find the exit door. Kill the two Zombiemen and then drop down the edge in the back of the room. Push the button down here to end the mission.
E1M3: Toxin Refinery
Go out this door and take a left. Kill the lone zombieman here then go through the door. In the middle of this room is a barrel. Wait for the two Zombiemen to get close and shoot the barrel to kill both of them. This will unlock:
Unlocked by 1,368 tracked gamers (92% - TA Ratio = 1.04)
Now, reload the save. Do the same thing, except don't shoot the barrel. Instead, lead them out of the room. When they are standing next to each other, take out your Shotgun, aim in between them and shoot to kill them both. Reload your save and repeat this two more times. When you do this you will unlock:
Unlocked by 1,275 tracked gamers (85% - TA Ratio = 1.08)
Then next follow the hall to the right and take the first left you can down some stairs. There will be a couple of enemies in here, so kill them. At the bottom of the stairs go left to find a button. Push it then return back up the stairs. There will now be a new path across from the door you entered this room from. You will need to be quick here. Take this path up some stairs and follow the path to the left. You will see an exposed wall (pictured below).
Go up to this before the platform raises and interact with it. The wall will open up. If you did not get there in time, just go back down the stairs and try again. When you get through, kill the imp at the bottom of the stairs. Continue through here and you will come to a pillar with a Supercharge on it. On the right side of this pillar is a switch, interact with it and take it. At this point, you should have 200% health and 200% armor (if you are close just pick the small armor and health pickups as we progress through the level. Make a save, you will want to end the level like this for an achievement. Save as much as you want as you go through the level, so if you take too much damage at any part you can just reload.
Go back up the stairs (quickly) and take the left path. You will see a similar wall as before, interact with it and go through here. In here is an imp, so kill him, then pick up the Rocket Launcher. If you face the entrance and look to your left there is a doorway in the acid. Run through it as quickly as you can. Around the corner, you will come to a platform with a switch on it. Flip this and grab the Backpack Full of Ammo. To the right of the switch is a slightly miscolored wall, interact with it and enter this secret room. In here is the Chaingun! The platform that dropped down will raise back, so take that up and drop down to get back in the room with the button that opened that hallway. Take the stairs back up and then through the door on the right to get back to the first area.
There will now be a bridge that you can cross over the acid pit. When you follow this, some walls will open up and there will be an ambush. There will be 4 zombiemen, an imp, and a pinky. When they are dead more walls will open and you can take this new path to the exit. If you take the exit with 200% health and 200% armor you will unlock:
Unlocked by 582 tracked gamers (39% - TA Ratio = 1.60)
You will also pop this:
Unlocked by 600 tracked gamers (40% - TA Ratio = 1.57)
This will take you to E1M9 which is a secret level (1/4).
Now, the secret levels do not have to be completed, they just need to be entered, so you may reload the save you made at the beginning of the level.
Go out the starting door and take a left and follow this hallway to an outdoor area. Keep following the linear path. You will come back inside and go left down another hallway. Partway down is your first Shotgun Guy (enemy 3/10). Follow this to get the blue keycard. Take it and then backtrack to the first room. When back here take the right path this time to find the blue keycard door. Go through it. Take the doorway on the left and follow it to a hallway that seems to lead to a wall with a second level above you. The floor will start raising into a staircase. Let raise and when it does there will be the exit door.
E1M4: Command Control
Okay, so there are two options here, use the speedrunning strategy or play the level traditionally. This strategy requires decent use of the strafe technique that is described in the General Hints & Tips page. I will describe both methods. The times are not extraordinarily different, but the speedrun strategy does save some time if you practice it. Another reason to get good with the speedrunning strategy is that when you do this mission on Nightmare in co-op there are far fewer enemies while taking this path.
Go straight out of the starting door and hang a left after the short hallway to go up some stairs. You will come to a circular room. Take the very next door on your right and then go right down this hall. Kill the imp on the other side of the window in here so he does not bother you. Now, you will see an acid pit. If you face this acid pith (so you can see the orange key card, you should see in the back left corner there is a very small ledge on the wall. The idea here is to strafe run off the staircase onto this ledge so you can follow this ledge to the opening where the yellow keycard is. This skips a decent amount of the level. If you are going for the speedrun here I recommend making a save before attempting this so you can practice it a bit. Keep reloading until you get it in a reasonable amount of time (I used 6-7 attempts as a metric, if I hit around that number without getting it I would start over, though this could have been too conservative, there is plenty of buffer time).
Once that is done grab the yellow keycard. Go right from where you came in here to find the yellow keycard door. Press the red button here and go through the door. Through here, take a right and turn the corner to find a staircase to the exit door.
Go straight from the beginning and follow the hallway. At the end of the short hallway go left and up the stairs to a circular room. There will be a closed-off portion of the level in here with four doors around it. Open any of these doors for an ambush. Go in here and grab the blue key (and the Chaingun). Now go out the doorway out of this room that was to the right of where you came in (west on your map). Take a left through here, go straight and open the blue keycard door on the right.
In this room, go right and immediately go straight down the hall. At the end make a left, and then take the left path here. In here, grab the yellow keycard. Continue through this room, and go around the corner to find the yellow keycard door. Press the red button here and go through the door. Through here, take a right and turn the corner to find a staircase to the exit door.
E1M5: Phobos Lab
From the start, go straight and then make a right. Follow this all the way to a door, and a dead-end at a balcony. This will trigger a floor in this other room to rise. Backtrack down the hallway you came from and hang a right to go up some stairs. Follow this path to the end to find the yellow keycard. Backtrack to the previous room with the acid pit. When you enter the room, you will see a wall that is brown instead of green like the rest of the room. Drop down here and interact with it for a secret. In here you can grab armor and some Rocket Launcher ammo (along with the Rocket Launcher). Follow the path to a wall. Interact with it and you will end up back in the first main room.
Take the only doorway you have not taken yet (the one on the left, directly across from the spawn). When you enter this room, take a left and go through the yellow keycard door. When you enter and drop down, take either the left or right path down some stairs. When you get to the bottom you will come to an open room with another pit of acid. Across this pit is a switch. Go over and hit it. Go directly across the pit again and interact with the wall here. You will find a hazmat suit in here. Then look to your left in here and interact with that wall to find the Chainsaw.
Leave this secret compartment and take the left staircase. Near the top will be a platform that dropped down (you may recall enemies being up here before). Walk onto this platform and ride it up. When it gets to the top look right and interact with the wall. The wall will raise. Walk forward and do this again. You will be in a new room.
Take a left in this room and walk on the red star on the floor. This will teleport you back to the beginning. Take the left door again but this time go in the acid pit and take a right through a new opening. In here is a Pinky (enemy 4/10). Follow this path all the way to the end. You will be in a room with a blue floor. In the back right is a button, press it. The wall will rise. Follow this new hallway to the end. There will be a switch and the blue keycard. Flip it. A staircase going down will have opened up, so follow it. At the bottom, look right and there will be a blue keycard door. Go through here, then hug the right wall until you reach the exit door.
E1M6: Central Processing
Go forward and hang a right. When you enter this room, in the very back will be the red keycard. Return to where you came into this room but the walls will be closed off. So stand here and kill the enemies until the door opens.
Now, run straight to the other side and take the red keycard door on the left. Now follow the path until you see a large opening on your left. In here is the blue keycard on a ledge. Take it, then backtrack to the four-way intersection near the spawn.
Take a left here through the only path you have not taken. In this room go right through a door. You will come to an area outside with a narrow path and an acid pool. There is an imp up on a platform above you on the right. We need this platform to lower. So approach the blue keycard door (but do not go through it). When you get close that platform should lower to reveal a room. Kill the enemies that came out and go into it. There is a radiation shielding suit. Interact with the wall behind it after grabbing it and the wall will open. In here is a different blue keycard door, along with a Backpack Full of Ammo. Open this door to get the yellow keycard.
Backtrack to the room before this (with the blue floor), go right, then go straight to the yellow keycard door. Follow this path up some stairs and down a hallway. You will see another yellow keycard door on your right and another staircase going down on your left. Take the stairs going down. Enter either opening on the other side of the room and follow the path to a switch, which you should interact with.
Go back to the base of the stairs, and on the right side of the room (if you are facing the stairs you used to enter this room) is a now-open door. Go through here and go down the steps on the right side. When you enter this room look to the wall behind you. There will be a button. Press it. Turn around and some walls should open up with more enemies. Go through the new opening on the right side of the room, and coming out of here should be a Spectre (enemy 5/10)
E1M7: Computer Station
Right out of the start, take a left and head into the room into the distance with flashing light (just hug the left wall). Kill the imp on the ground floor here and the lift will drop down. Stand on it and wait for it to go back up. Kill the enemies here and follow the path to get the yellow keycard. Drop down and hug the left wall again, and go through the yellow keycard door.
Through here, go straight, turn the corner and keep going straight. You eventually come to a set of stairs. At the top, a pillar will drop down. Continue past it and follow the hallway to the right of the door. Hug the left wall while going through here. Go through the door at the end of this hall, then use the lift in the back left of the room. Follow this path to get the red keycard.
Backtrack to the room with the pillar. Run past it to get it to come down again. When it lowers, walk onto it and face the closed door that you ran past before. You will see a radiation shield suit. When the platform is partly raised above the railing, run off the platform to land in the acid. Go grab the suit. In this same spot, near you, is a red button. Press it. The wall will open up and you can run up the stairs to find a switch. Use it.
If you did not get 200% armor and health before here is another opportunity. Go back down the stairs and hang a right. You will see a brown fat pillar in the acid. On the right side of the pillar is some armor. Then go towards the window on the other side of the room and follow the path along the left of this window. Grab the Supercharge here, look right and interact with the wall to open it up.
Go left here to find get to the red keycard door. Open this door and run to the end to get the blue keycard. Go right down to the end of the hallway. Go through the yellow keycard door, and hang a right until you see the blue keycard door on the left.
Go through the blue keycard door, climb the stairs, and go straight down this hall. Follow the path to the end and interact with the green button. Return to beginning of this room (at the top of the stairs after the blue keycard door). The door on the other side of the room should now be open. Go through this door, and the hallway will take you to the exit door.
E1M8: Phobos Anomaly
Start by pressing the red button in front of you. Shoot the barrels below to kill all the Pinky's below. In this room take a left and go through the door. In this room, there is a Chaingun and ammo to your right and a Shotgun and shells to your left. Fill up on ammo then go to the end of the hall and click the green button. The wall will lower. Hop on and wait for it to raise you up.
Time for two Baron of Hells (enemy 6/10). Take out your Rocket Launcher or Chaingun and unload on them. Also, just note the red floor in this is not lethal so feel free to run around on it to avoid the Barons' attacks.
When they are dead, the walls around you will drop. Go straight from where you took the platform up. There will be a U-shaped structure with a switch. Interact with the switch and let the stairs rise. Take the stairs up and walk on the Baron platform at the top. You will teleport to a dark room full of enemies. Whether you kill them all or die doesn't matter, this will end the episode.
You should pop:
Unlocked by 998 tracked gamers (67% - TA Ratio = 1.22)
The Shores of Hell
Just a note for this episode, make sure you have pistol ammo going into E2M8. This is the only place a Cyberdemon pops up and you will need pistol ammo for an achievement during this fight.
E2M1: Deimos Anomaly
Go forward and hang a right. Follow this to the end to get the blue skull key. Backtrack to the spawn, then use the teleporter in the corner.
Follow this path until you reach a teleport. On the wall near this teleporter is a switch. Flip this switch and a button will come out of the ground. Press this button, then go through the teleporter.
In this room are two skull switches in a divet in the wall on the left, one switch facing the into the room, the other on the left wall in the divet. Press the one facing into the room. The wall to your right will drop, go through here and go around to the left to find the blue keycard door and go through the teleporter in here.
Walk into the room and turn around. You will see a path to the left. There will be a Lost Soul (enemy 7/10). Kill it. Further into the room is a red button on the right wall (relative to the direction you came in). Press it then go down the hall where you found the Lost Soul and climb the new stairs to press the other red button. Turn around and go through the teleporter straight from the staircase. Continue forward for the exit door.
E2M2: Containment Area
Go forward, turn the left corner and then the right corner by the berserk powerup. Take this into the green hallway. At the intersection here, take a right. Go all the way to the end, grab the radiation shielding suit and follow the hallway with the acid ground to the end. Above you, you will see a window. Face the window and look slightly to the right so you are facing the way you came. Save here just in case in case you make a mistake, you only get one shot at this. Go back and forth against the wall with window above and mash . A platform next to you will begin to rise. Walk onto it before it gets too high. Wait for it to rise to the top, where you will find the exit door.
Go forward and take a left at the barred windows. Then go forward. Follow the hall straight through the acid room into the room with the Shotgun. Take a right and go straight into the lava river. Go up the stairs that are on your right to get the Plasma Gun. Drop down here and grab the blue skull key.
Leave this room through the only door, take a right, go to the end of the hall then make a left back through the Shotgun room and into the room with the small acid pit. On the other side of the acid pit is a section of wall barred off by two metal bars. Interact with this section of the wall and it will rise. In here, go straight and follow the path to the blue keycard door. Follow the linear path until you reach a dark room. In this dark room hug the right wall until you reach an exit. In this new room cross the acid pool and then follow the hall to the exit door.
E2M4: Deimos Lab
Go forward to the teleporter in front of you. Go forward then hang a left through a series of platforms separated by acid. Continue following this until the end. when you will enter a series of blue hallways. Follow this until you have to make a right, then you will come to an intersection. Go straight and you will find 3 imps running around. Open the door, and kill these three along with the Pinky on the other side of the door quickly. Kill them fast enough and you will pop:
Unlocked by 663 tracked gamers (44% - TA Ratio = 1.49)
Go through the door that the Pinky came from.
In this room press the red button to lower a platform. Get on the platform and wait until it rises again. Grab the blue skull key that is up here. Drop down and go back through the door you came in. At the intersection take a left and go through the blue skull key door. You will enter a red hallway. You will reach a yellow keycard door. Look to the left and you will see the yellow skull key. Run straight through this platform to the other side of it while picking it up in the process. Don't linger as the block above the keycard will start to fall and deal a massive amount of damage. Then go through the yellow keycard door.
Go left through this curved hallway. Pass the hallway on the left and you will find a gap in the floor against the wall. Walk into this gap to fall down and interact with the wall on the left to open up a secret. Pick up the Plasma Gun in here and then head through the teleporter.
Go down the only path that leads from this room. At the bottom of the stairs you go down will be a Cacodemon (enemy 8/10). Kill it. Then look to the small hallway from where you came from and go through the teleporter. Take a right down this hall. You will come to a pit with lava. Over this pit, look to your left. You will see a small square platform. There is a skull switch here. When you trigger it run back into the lava pit and onto the platform that is now raising. This will take you to the exit door.
E2M5: Command Center
Leave the spawn and take an immediate right. Follow the path to the stairs going up. At the top, go to the right to find a skull switch. Activate it and go through this hallway and staircase to the end. There will be another skull switch, activate this one also and go inside. If you were unable to get Cookin' With Plasma before, here is another opportunity.
Face the wall you came from (opposite of the open door), there are two skull switches. Activate the one on the left. In the new room, there is another switch on the right. Activate that one aswell. Leave the room and go over to the right, where there is a staircase. Go up to it and you will be teleported. Turn around and there will be a lion's head on the wall. Interact with this to open up the wall. Go through it onto the teleporter which will take you to an exit door, and put you in the secret level (2/4), E2M9.
Leave the spawn and take an immediate right. Follow the path to the stairs going up. At the top, go straight to an outside area. Go to the other end of this area to find a skull switch. Activate this and go into the room. Go through the door on the right. If you go into this room and go around the corner to the left, on the left wall is another skull switch. Activate it and go through. Follow this path up a set of stairs and you run into yet another skull switch. Activate it, go through and take the left path.
When you get to the bottom of the stairs, there is a skull switch on the right. First, grab the radiation shielding suit, then interact with the switch. A door will open and go through and follow the stairs up. There will be another skull switch. Activate this, then activate the next one that is right in front of you. In this new hall, make a right and go down the hall. At a four-way intersection take the right path and follow it to the exit door.
E2M6: Halls of the Damned
This is probably one of the most, if not the most, confusing missions in the game. There is however a glitch that lets us skip almost the entirety of the mission, but it is finicky and difficult to pull off. It is at least worth it to try, and will tremendously help with the Nightmare run. However, as per before, I will describe both the glitch and the "normal" path to the end.
As for the glitch, the process is this: There is a corner you will run at, you will need to adjust the stick such that you glitch out of the level. You will know this happens when your gun begins to blur on your screen. When this happens you can go straight over to the exit room, and with the right positioning, you can press the exit button to end the level. To clear this up more, here is a video that explains it.
All credit for this video goes to Oxyde.
Go forward, grab the Rocket Launcher. Open the door and use the skull switch in here. Backtrack to the spawn, then take a right into a new area. Go to the other end of the area. You will find a Berserker powerup on a ledge across an acid pit. Press the red button here to raise some stairs so you can get to it.
Grab it. A new door will open over on the left in the acid pit. Follow it to the end, you will find a switch. Trigger then run back to the big area, and take a left and go through to the locked exit door. Go through the other door here. Kill the enemies in this hallway, follow the hallway to the left and you will see the blue skull key. This will spawn a Pinky and release two imps. When they are dead, face where the blue keycard was. This corner on the right is the corner you need to glitch out of. So face the corner and aim at the right wall, but not straight at it, make sure you are ever so slightly looking to the left, towards the other wall. Go to the right and run back to the left into the corner. If done properly you will glitch out of the map. IF it doesn't happen immediately, fiddle with which way is being pointed. If you can't get it, adjust your aim ever so slightly.
When you are out of the map, go over to the exit door. You will notice somewhat of a couple of pillars. Go to the right of these and you should be able to see the exit button. You will need to align yourself such that the button itself is just a red sliver, and you will need to aim slightly to the left of the button (so that you are aiming behind it essentially).
Remember, this glitch is finicky, even for those who have done it before. When I was writing this, I got both parts of the glitch done on the first try. When I went to record it, it took me 7 minutes. It's very precise, so I implore you to keep at it. For those that don't want to bother with this, or cannot get it, up next is the "normal" method.
This is a good opportunity for the achievement Guns Are For Wusses. Just killing the enemies with your fists until you hit 25. That will unlock:
Unlocked by 482 tracked gamers (32% - TA Ratio = 1.76)
Go forward, grab the Rocket Launcher. Open the door and use the skull switch in here. Backtrack to the spawn, then take a right into a new area. Go to the other end of the area. You will find a Berserker powerup on a ledge across an acid pit. Press the red button here to raise some stairs so you can get to it.
Grab it. A new door will open over on the left in the acid pit. Follow it to the end, you will find a switch. Trigger then run back to the big area, and take a left and go through to the locked exit door. Go through the other door here. Kill the enemies in this hallway, follow the hallway to the left and you will see the blue skull key. Across from that is a brown wall. Interact with this to get the Chainsaw.
Follow the hallway back and circle around to the left, there is a switch. Use it. Turn around go on the left path again. You will come to two openings that lead to an area with wooden walls. Take the left door. You will come to a three-way intersection. Take the middle path. Follow it straight and you will come to a door. Go through this door.
Once in here, make an immediate right. Then go straight and hug the left wall around a corner to find the red skull key. Backtrack and make a left when you get back to the white hallway. At the end are two doors. Take either door. Go down this next hallway and open the door at the end. In this door, there will be a green button. Press it and turn around. Follow the hall here upstairs. When you get to the end of the hall there will be 4 paths. Take the one immediately to your right. Go around either path in this room to the other side to get the yellow skull key. After this, leave the room from where you came, and take the path you came from.
You will need to backtrack all the way back to the main hallway. Take a left and just follow it back to the end where you will find the exit door.
E2M7: Spawning Vats
Just a note for this mission, remember to make sure you preserve some Pistol/Chaingun ammo. You will need it for the next mission for an achievement.
Right from the start take the door on the left. Follow the path straight, ignore the elevated door on the right and keep going. You will go left around a corner down some stairs. At the bottom, immediately take a right and go to the switch at the other end of the room. Press it, the panel will lower, and you can proceed. On the right side of the room will be the blue keycard.
Backtrack to the initial spawn. Now take the right path. You will see a blue key door. Open it. Grab the Chaingun on the right then take the left path. There will be two ways to go, stick to the left. Follow this path to the end to get the yellow keycard.
Once again backtrack to the blue key door. Make a left out of this door and follow the path. On this path is an invincibility pick-up. Feel free to grab it. At the end of the path, you will come to a room with the exit door. You could take the Rocket Launcher, strafe run backwards and shoot as you go off the ledge to propel yourself over to the exit door. If you want to try this method, feel free, but it is not worth the effort here. So go through the only other door here that you can open.
Go through the hall here, and make the first right. Then go through the yellow key door that is on the right at the end of this hall. At the other end of this room is a path. Take the path to find a switch. When the switch is activated, go back into the previous room and the red key card should spawn. Backtrack to where the exit door was. Just a note for this section, even on I'm too Young to Die, there a lot of imps around where you grabbed the red key card, so this is a good spot for both Groovy and Cookin' With Plasma.
When you get back to the room with the exit room, there is a red key door. Open it. In here is a button. Press it. This will reveal another button. Press this one too. A bridge will rise, letting you get to the exit room.
E2M8: Tower of Babel
Turn around and there is a pillar with a button on each side. Then go through each door and get whatever powerups there are. Be quick, as the door will close behind you.
When you go outside the Cyberdemon (enemy 7/8) will spawn. Unload about 200 rounds from your Plasma Rifle. This should get his health down far enough that a few shots from the pistol should take him out. Make saves as you deal damage to him, just in case you do too much. It is not necessary for this, it just makes it so you won't have to redo the entire fight if he dies by something other than the Pistol.
When the Cyberdemon is dead, that will be the end of the episode. That will unlock:
Unlocked by 638 tracked gamers (43% - TA Ratio = 1.52)
If you finished it off with the Pistol you will have also unlocked:
Unlocked by 441 tracked gamers (30% - TA Ratio = 1.83)
E3M1: Hell Keep
Start by interacting with the closed eye that you spawn looking at. This will raise you to the surface. Run for the door ahead, and interact with the skull switch to the left of the door to open it. Once in here, hang a right and follow the linear path until you get to the exit door.
E3M2: Slough of Despair
Go straight and take the left-most path. Hug the left wall until you come to the blue skull key. Go back the way you came and when you pass over a bunch of ammo and health items, head to the left into what looks like a dead end. The wall will drop. In here is a blue key door. Open it and activate the switch. Turn around and go to the right to find a portal. Go through the portal to end the level.
Start by going straight and then up the stairs. Then take the steps in the back right of the room. Take a right at the top of the stairs and follow it to the end. Drop down, then go down the metal steps. At the bottom, grab the blue skull key.
Go back up the steps. At the top, there is a platform made of bone. To the left of this is a closed eye switch. Switch on the eye, ride the platform up, and drop down. After you drop down, go up the stairs on the other side. At the top, take the right path then drop down. When you hit the ground, turn around and take the right path down a short set of stairs and then take an immediate right, go down to the end of the hall, and make a left when you reach the door. Continue forward into this new outdoor area and go through the blue key door over on the right. This will take you to the exit door.
E3M4: House of Pain
Go straight and up the stairs. In this outdoor area, there are three switches on the other side. Interact with the one on the right. Then take the path on the right, cross the hallway and follow this other hallway. Go straight and hug the right wall. This will take you to the blue skull key. Go back the way you came and make an immediate right and go around the corner. There are some barrels and door in the distance, go to the door.
Go through this door, then through the next. In this next room, there is a door and in front of is a red portion of the floor. To the right of this is a blue panel. Step on this and the door will open. Head through. Follow this hallway until you get to two pillars with skull switches on each side of them. On the left pillar, activate the left switch. Once that is done take the left path and second door on the left will have the yellow skull key.
Go back to the two pillars and face them in the way you did when you first entered this hall. On the right pillar activate the front and left switches. Go down the right path this time and go into the second door on the right. Open the yellow key door. In here grab the red skull key. After this go into the other doorway that you passed on the right. In here is a red key door. Enter it and follow it to the end where you will have to drop off a ledge. When you drop off, take a right and there is a panel that is different than the rest of the room. Interact with it and it will open up. Follow it to the end for the exit door.
E3M5: Unholy Cathedral
Another one of the very confusing levels. Go straight and through the left door and go down the hall to the left. There will be two doors. Go through the one on the right and go through the teleporter. Turn left and go through the other teleporter over here. When you teleport, walk backwards to teleport again. Then take the door on the right. Follow it to the silver doors. Here, there is a red pillar with an opening in it. Walk through this and the silver door will open. On the other side of the room are two skull switches. Trigger the one on the right. Then go to the left into the back left of the room to grab the blue skull key.
Face the door you came from, and to the right of the door is a platform with a block going up and down. When it is raised, go onto the platform to teleport again. In this room go to the left door and follow it to the blue key door. As you enter, look to your left and you will find the exit door.
E3M6: Mt. Erebus
Right from the beginning, look right and go forward. Pass a mossy building on it's right and you will see a pool of lava. At the end of this pool is an area where you can drop off. When you drop off, in the back of this area is a blue square with the secret exit in it. Go towards the right side of this square and aim towards the back of it (if you look at your map you should be facing roughly northwest. Mash as you go back and forth on the side. This should trigger the exit and take you to E3M9, the secret level (3/4).
At the start go right, and hug the wall on the left. At the entrance of a big green building (not the mossy building, the one to the left of that) is the blue skull key. Enter this building and look at the left wall. On the floor is a candle. Interact with the wall behind it. Then step through the teleporter.
When you are outside you will see below you is a red square. Run into it. If you miss it, run around the back of the structure that you ran off of, and there will be a small divet in the building with 3 demon faces on the walls. Walk into this and you will teleport back into the building. When you drop down into the square, take the teleporter here. In this new area, turn around. Go down the hall, take the left path and deactivate the skull switch. Then backtrack to where you came from and exit through the open door. Take a right and hug the right wall. You will see a stone wall along with a brick structure in the lava. Follow this brick wall until you come to an opening in the wall. Follow this path to the exit door.
Go straight out of the start and make a left when you reach the lava pit and go through the doorway here. Just hug the left wall until you reach the blue skull key. Return to where you came from by hugging the right wall after you turn around.
Go across the lava and go to the other doorway (the door to the right relative to where you started). In this room, take the blue key door on the left. Jump off the right side of the platform here and take the stairs up to the other platform. At the back of the room is a hole to drop down into, do so. When you get here there will be a few radiation shielding suits, grab one or two and take the left path.
Go straight until you see another piece of land with more radiation shielding suits. Enter here and take the right path. Follow this path and hug the right wall. You will come to a teleporter, do NOT take it. Instead, take the left path just before the teleporter. At the end of this path is the red skull key. Interact with the lion head switch and then use the skull switch in there. Turn around, go straight and take the teleporter. Make a left and again hug the right wall to get back to the center area.
When you get there, take the door on the left, the only door in this central area you have not taken. In here there are two pillars. Behind both of these are doors. Take the door behind the right pillar. When you get here, there is a corner in the middle of the platform, close to the platform next to you with enemies on it. Straferun off this corner to get the yellow skull key. If you are having trouble with this trick you may take the left pillar's door to get a switch to bridge the gap, then take the right pillar's teleporter to get the key.
Teleport back and leave this room. In the center of the central room is a teleporter. Take it. Then strafe run across the gap (this one is a little easier to pull off). Go through the yellow key door and activate the switch in here. Return to where we got the yellow skull key (go through the door in front of you and take the right pillar's teleporter). Now go through the door on the left and hug the right wall. You will come to another pillar, similar to the other ones. Take the teleporter in here and go through the exit door.
From the start go straight. You will enter a big open area. In the middle is a small building. Open it and grab the Plasma Gun. Use this to unload on the Spider Mastermind (enemy 10/10). When it is dead the episode will end. You will pop:
Unlocked by 517 tracked gamers (35% - TA Ratio = 1.69)
That kill will also be your last enemy, which unlocks:
Unlocked by 506 tracked gamers (34% - TA Ratio = 1.71)
If your collective time for all the missions is under 2 hours, you will also unlock:
Unlocked by 122 tracked gamers (8% - TA Ratio = 3.49)
Thy Flesh Consumed
E4M1: Hell Beneath
Go straight and take a left. Follow this path to a demon switch. Use it then go back and take the right you did not before. A new opening will be there. Go through there. In this new room and go right. When you go around the first corner you will see a ledge to drop down and a doorway. Go through here and go to the end. In this last room is the red skull key.
Go back where you came from, and on your right is a platform before the exit. Interact with it to make it drop down. Get on it and let it rise you back up, then run off the ledge back to where you came from. Now that you are back in the main room, go through the red key door. In this room is what looks like a wall, but you can actually run to the right or left of it and get behind it. Behind it is the blue skull key.
Return the to the doorway on the opposite side, and follow the path to the right as before, but this time continue until you reach the blue key door. Go through here for the exit portal.
E4M2: Perfect Hatred
Start by running up the steps on the left and across the gap. When you reach the other side look right and activate the lion switch here. A wall behind you will open up. Run across the gap to that opening and then drop down to the lava. Turn around and you will see another lion's switch. When you press it, run across the lava and get on the now-rising platform. When it rises, run across the gap to the other platform. A wall will open and a Baron of Hell will come out. The yellow skull key will be in here. Take it. Backtrack around the room and run over the gap from which you initially entered this room. From here jump down to the right and go through the doorway in the back-right. Now, go up the staircase and at the top, go up the stairs on the right and run across this gap. Activate the yellow key lion switch.
A wall will rise to your right. Run across the gap to that platform and then go into the cave that is on the right from here. Drop down here and hug the left wall until you reach a staircase. Go up the stairs. At the top, through an entryway on the left is a Baron of Hell and the blue skull key. Go through the teleporter. Now climb the left staircase again, but this time, go straight to the blue key pillar.
Climb up the stairs and when you reach the top, turn around and go back down them. To the left of the bottom of the stairs is a new small staircase, and a teleporter. Go through it. You will spawn on top of the Cyberdemon. The Cyberdemon will die and here, you can pick up the BFG. At this point, there should be two Cacodemons flying around. Make it so you only have one of them in your view, and kill it with the BFG. This will pop:
Unlocked by 566 tracked gamers (38% - TA Ratio = 1.62)
It does not necessarily need to be these enemies, it just has to be one singular enemy killed with a shot of the BFG. It can be any type of enemy. Make a save here.
Go back down the stairs and onto the teleporter again. Take a right and jump off the platform into the lava. There will now be an open door. Go through here into the exit. This will give you access to E4M9, the last secret level (4/4). It will also pop:
Unlocked by 214 tracked gamers (14% - TA Ratio = 2.63)
Reload your save. Go straight and then take a left through the door here. At the end of the hall is the normal exit.
E4M3: Sever the Wicked
Run straight off onto the ground and go down the stairs in front of you. Take a left at the bottom and go up the stairs. Follow the hall here through a door and drop down into the pit and go straight into another room. When you enter this room, turn around and interact with the lion switch. A platform will lower, on this platform, grab the red skull key.
Enter the room where the switch was and take a left. You will find a room with the Rocket Launcher in it. Go straight into the wall and interact with it for a secret hallway. Follow this to the end and take the teleporter back to the spawn. Look right and go through this path, opening the red key gate. In the middle of this area is a support beam. On the other side of this beam is the blue skull key. Continue straight off this area to a lower area. Take a right and jump down into the lava and go through the red key door.
In this room go up the stairs you find and follow it to the blue key door. Follow this room to the exit teleporter.
E4M4: Unruly Evil
Go straight out of the spawn, activate the lift in front of you and ride it up. Go to the right and follow the path around the perimeter of this area. There will be a lift you can activate to lower. Ride this back up. Go through the door and hang a left. You will see a room with the red skull key. Once you have that, turn around and go left around the corner to the red key door. In here, look to your right, and activate the demon face switch. The lift near the exit will lower. Ride it up and take the teleporter over on the left side of this platform. In here, look to your left and activate the demon switch in here. Now drop down, activate the first demon switch again to ride the elevator platform. This time take the teleporter on the right. Look to your right and activate this switch. Once again drop down and activate the switch here to ride the elevator up. Now you may go through the exit gate into the hole in the ground to end the level.
E4M5: They Will Repent
Go around to the left at the beginning and go down the stairs to the door. Go through it and hang a right and hug the right wall until you get to a door, which you should go through. At the other end of the room is an elevated platform elevator. Approach it and it will drop down. Hop on it and ride it up. Over on the right, in the corner, is the red skull key. Grab it.
Drop off this upper lever and go to the back right of the room, where the red key door is. Go through here and follow the hallway until you go down an elevator and into a big room with a lava pit in the middle. Jump down into the lava and make a left, to grab a radiation shielding suit. From here go up the stairs, and follow the path until you see another way to jump down on the left. Jump down here. Follow this and bear right. You will come to a room with a window. Run out of this window to drop down on the exit button.
E4M6: Against Thee Wickedly
Go straight out of the spawn and hug the right wall until you come to a new area. In the new area drop down into the lava river in front of you. Follow this to the left. Grab the radiation shielding suit on the left, and jump off the ledge here. The key to this level is the teleporter you may have noticed when jumping down here. It is on a very tall brown poll. Depending on which side you take the hidden lift up and into the teleporter will determine where you end up. So there are four different places this teleporter can take you. Interact with the poll while facing to the east (the way you were just running when you jumped off the ledge.
You will teleport to an area above an imp and a Shotgun Guy. Kill them and jump over to them. Go forward to where they were, then follow the path to the blue skull key. Jump back into the lava where you were and take the same side of the pillar up through the teleporter (the west portal). You will be back in the same place. Turn around and you will see a platform relatively close to you. Straferun off the platform you are on to this other platform. Follow the path to the red skull key. Backtrack and a new bridge will rise to your right. Follow this over and then another bridge next to it. Turn right and activate the blue key lion switch.
Turn around and look to your right and you will see the yellow skull key. Go up to the platform it is on. This will open the door that was opposite of the blue key lion switch. Go in here for a Rocket Launcher and on the left wall is a switch, use it. Then go back out and get the yellow skull key. Backtrack across the bridge, but don't cross the second one.
In this room on the right is a teleporter. Take it. Go straight and at the end is a big rock structure. On the left side (the side you would be facing if you were facing the building) is a red key door. Open this and hit the lion head switching inside. Leave this room and hang a left around the corner and go onto the teleporter pad. Follow this pad for another teleporter and a BFG. Here a Cyberdemon will spawn. I recommend a save here, it can kill you very fast, even on I'm too Young to Die. Turn the corner to find him and there will be an invincibility powerup here. Grab that and kill it with the BFG or the Plasma Rifle. When it is dead, interact with the gate that it was guarding and go over to the exit switch in the back left of this small area.
E4M7: And Hell Followed
Go straight down the hall and make the first left and follow this around to the left. Go through the door at the end of the hall. In here turn right, and in the far left of the room is the red skull key. It appears to be up above you out of reach but walking into the wall underneath it will give it to you.
Go back through the door you came in here from and then make the first right and the first left. Continue down to the door and go through it. You will now be outside with a lot of enemies. Go straight and fall into the pit here. Go to the left, grab the radiation shielding suit and continue this way. Open the red key bars here and then take the elevator up. At the top, interact with the skull switch. Another switch will pop up, interact with it (it won't change from red to green, just ignore this). Go out the window. There will now be a platform raising the bridge the gap between your side and the middle. Go to the middle platform and wait for a switch to come out of the ground. Interact with it when it does to end the level.
E4M8: Unto the Cruel
Go straight at the spawn until you come to a big circular area. Take the left path, interact with the demon wall and take the teleporter behind it. Go up the stairs in front of you, and take a left to get to the blue armor pick-up. Follow this path into a building. There will be a skull switch on the wall, press it and drop down. Follow this path straight to the end to get the yellow skull key and interact with the middle wooden panel to reveal a teleporter. Go through it.
Go forward and fall off the platform that you are on. Go to the right and hug the wall on your right until you reach another teleporter. Go through it. You will be back in the circular room. This time go right and interact with that demon door, which will reveal the red skull key. Go back to the middle and on either side of this central pillar are yellow key and red key walls. Activate them to reveal skull switches. When you hit both a platform will rise to bridge the gap to the other side of the room. Take this door to the boss. When the Spider Mastermind is dead, the structure in the middle will disappear and you can take the hole in the floor to the exit for the end of the game.
You will unlock:
Unlocked by 399 tracked gamers (27% - TA Ratio = 1.93)