This guide and the associated videos are not mine. I do not claim any ownership of them. They are not specifically for this achievement, but rather show methods of speedrunning the original game on Serious difficulty, which includes an incredible number of tricks that can save you hours of pain. At the top of the linked page is a Tourist guide and videos; scroll halfway down the page to get to the Serious difficulty portion. All thanks go to Arran 'ShadowWraith' Kelf, Drew "stx-Vile" DeVore, and Bart 'TheVoid' de Waal.PLEASE NOTE: As o DEEVIUS o pointed out in the comments, these videos come from the original PC version of the game. Every now and then, one of their tricks will not work on the 360 version. However, you can compensate for a lot of the little differences and make about 90% of the secrets/glitches/shortcuts function properly. You will need more health than they do for rocket jumps. You will also sometimes need to do 2 rocket jumps when they only do 1, as they do not take you quite as high in the 360 edition. Keep your eyes open and adjust the way you approach a shortcut based upon how the physics have changed.
The original guide can be found here: http://speeddemosarchive.com/SeriousSamFE.html
I have included videos of each individual level. A full-game video is also available on the site. Below are the speedrunners' comments, followed by the videos.
"==== Level 01 - Hatshepsut - 0:35 ====
This was the only run where I intentionally used a Kleer for a slight speed boost. They really hurt, so I don't get hung up on it, but since the run was so short, it might have helped optimize the time a bit. Also, is it just me, but does a Kleer seem like the skeleton of a Quake Fiend... large scythes for arms, hooved feet, leaping attack... hrm.
==== Level 02 - Sand Canyon - 1:45 ====
The first trick jump, which uses a Kleer as a step over the gate, is rather tough to stage... it's hard to see in that dark tunnel, so getting the jump immediately made me happy. In the Marsh Hopper (exploding toad) room, killing the headless enemies quickly makes the toads appear faster. The armor for the end run was entirely optional, but requires quite a bit of luck to survive without it. Overall I'm pleased with how this one turned out, despite getting hung up a bit at the very end.
Also, as an aside, I normally let the final cutscene play out completely in these demos, but the slowdown there got so horrible that I cut it short early. I was afraid for the rest of the runs where I would be avoiding large numbers of enemies, hoping the slowdown wouldn't get too bad, but it seems this was the worst case scenario. :)
==== Level 03 - Tomb of Ramses - 1:46 ====
I'm very happy with the way this one turned out. I had two monster boost tricks and both were implemented without much loss of time here. In the tunnel after the secret passageway, with virtually nothing going on, I jump once while running through it. This jump was to avoid a trigger that will close the door in front of you and trap you with an Arachnid and some kamikazes. I discovered this trick by accident and was quite glad, as I was using the kamikazes to painfully jump over the door to get out of the trap, putting me in an unhealthy position for the remainder of the run.
==== Level 04 - Valley of the Kings - 4:35 ====
This was the last run done for the pack, replacing a 4:50 run that I wasn't happy with and eventually couldn't ignore. It's one of the more frustrating runs in the game on the fastest route. In the valley, I don't kill the Gnaar (beartrap teeth creature) or the Werebull, as their deaths will cause many more enemies to appear in their place. I just let them trail behind me as I run for the temple. The Reptiloid (green magic missile caster) has to be killed for the rocket launcher to be appear, which in turn causes the boss to appear when it gets picked up. At this time, the Werebull is still running around trying to get me, and sometimes I can actually get him stuck on the left side of the platform so that he'll eventually stop trying to chase me. This is luck-related though, so I sometimes have to kill him. The boss takes exactly 14 rockets to kill, incidentally.
Inside... I hate that rocket jump to the key. It's easy to miss grabbing the key entirely. This is also the room where you can ghost around the map by rocket jumping on top of the ceiling. I don't do this, though, having made it against the rules. You could fly right to the exit if you wanted, though. :)
Rocket jumping over the wall of darkness... self-explanatory. At the cage trap with the heart, it's possible to avoid getting caught inside, but the door to the next area will not open until the trap has played out. The cage provides protection against the Kleers anyway.
==== Level 05 - Moon Mountains - 1:41 ====
The first secret level of the game. There's not much to explain here, since the run is fairly straightforward. There's two shortcuts that I use here, but both of them actually count towards the secret tally, so there's really nothing that I can take credit for, here. At the very end, I rocket jump over a werebull that spawns in front of you, though this was probably hard to see in the demo. I'm also quite happy with this one.
==== Level 06 - Oasis - 3:25 ====
This is a luck-oriented pain in the ass on the fastest route, since the Bio-Mech that spawns inside the building can keep you from advancing too quickly. I had to cancel out his rocket attack at close range with the tommy gun to make it by. In the boss room, you can rocket jump on top of the outer walls in this room, but that's rather boring. :)
Also, it's worth mentioning that the two health potions that can be found in the boss room are both booby-trapped and cause more toads to appear, which aren't part of the boss meter. The one that appears in the middle of the room partway through the battle is particularly unforgiving...
==== Level 07 - Dunes - 0:48 ====
Special thanks to LarvaExotech, who contacted me sometime after the original demos were posted and revealed to me a trick for finishing this level quite a bit faster than before, making the final battles unnecessary. I assume that he/she is close to the Serious Sam community, as this trick's existence would have been difficult to predict, otherwise. Basically, this run exploits a "thin door" bug whereby the player can initiate the final cutscene of the level through the exit door and end the level early. This is done by taking damage and forcing Sam in the direction of the door, apparently reaching through it briefly to activate the end-level trigger. LE described this trick using a Bio-Mech for the required damage boost, but some rocket splash damage from your own launcher is sufficient. Although some other levels in TFE come close, this is the only level that I know of where it actually works. As a word of caution, for this trick to work, you MUST end the cutscene before it finishes, because you won't end the level if you do. Instead, you'll be returned to Sam's point of view, stuck inside the door, unable to turn, and with a red screen. It's weird, but true, so pressing fire sometime in the final cutscene is necessary to move on to the next level.
That said, the level became much shorter, and so I also felt obligated to implement some time-saving Werebull jumps to cross the desert faster than before. These jumps are rather uncooperative, as you can either take a lot of damage from the hit or no damage at all, and the direction is tough to control. However, for such a short run, I felt it necessary to do so... if just for the practice, since I've found at least one place in The Second Encounter where such a jump is needed because the rocket launcher isn't available yet.
This was a lengthy session, working down the time second by second, and I don't feel like doing it again. It's not that fun, so I hope the result was an enjoyable 48 seconds. :)
==== Level 08 - Suburbs - 1:53 ====
This was the first level where I thought I'd have to slow down and deal with the battles that are scripted by the game, but by choosing which enemies to kill and which ones to ignore, I can make my way through without having to get too hung up by the hordes. In the first half, I briefly retreat to the secret corner until the situation calmed down a bit. I'm normally getting chased by several Reptiloid projectiles, as well as the Werebull, so reaching the door quickly required some sacrifices on my part. In the second half, the screen changes briefly when I hit the two switches that open the way to the sewers. This is the game trying to initiate some small cutscenes showing what the switches do, but it assumes that the player would have cleared the area before hitting the switches. I make those cutscenes as short as possible. :)
==== Level 09 - Sewers - 1:38 ====
I had a hard time seeing the electric fish, so I sometimes couldn't predict exactly where they would appear in the final underwater segment. I only had the general idea of their locations. I don't think I lost any time, though, since I kept moving on the right path as they appeared.
==== Level 10 - Metropolis - 9:18 ====
I'd say this is the run I'm the least satisfied with, as it was rather boring on the shortcut route. As such, I played a run where I got to the end and dealt with the final battles in a manner that wasn't too embarrassing, but didn't spend a lot of time shaving away the seconds. For future improvements, it's possible to be right by the door as it opens, though that greatly depends on some blessing from the Kleer horde.
==== Level 11 - Alley of the Sphinxes - 6:16 ====
Perhaps the first run to use the new Number of the Beast, not that it matters. This run is similar to Dunes, in which I avoid a large portion of the battles by rocket jumping past the segments before the final arena. For each item that is placed in one of the four corners of the last arena, a different set of enemies will appear. I tried to move from each corner of the arena to the next so that some collections of enemies would overlap with each other, but not becoming too overwhelming. A shame that minigun and laser ammo was more limited here.
As I found out, only the largest of the lava golems need to be killed for the final door to open, not any of his offspring. I move towards the door without getting too close to the boss as his melee attack is, not surprisingly, rather painful.
==== Level 12 - Karnak - 7:07 ====
Another run like Metropolis. I demonstrate the trick jump at the start, run off to the end, giggling the entire way (maybe) and then basically do a walkthrough of the final battles of the level. I'm not sure why the rocket jump off of the beheaded soldier's head seemed to get more height, but that was the case here. I got knocked away from the exit door right at the end, so that's one possible improvement.
==== Level 13 - Luxor - 5:34 ====
For this run, I'd like to give credit to someone named Prestige, assuming that was the first person to discover the trick seen here:http://files.seriouszone.com/download.php?fileid=265
This trick makes the level rather quick like Karnak and Metropolis, but also makes it just a walkthrough of the final battles of the level. I know some people were disappointed by the lack of action in these instances, but it did allow me to speed up the final battle when it was reasonable to do so. In the final arena, you must collect the four Ankhs and place them on the center pedestal to make the final door open. They appear one at a time, and you must place that Ankh before the next one will appear, but at least they'll always appear in the same places.
Also, near the start, I use a seemingly useless RJ over one of the walls to get to a nearby courtyard. This is used to avoid a trigger that would bring in some tough monsters (large lava golems, reptiloids, etc) that would cost even more health and time to dodge, since they will lead their attacks.
==== Level 14 - Sacred Yards - 1:30 ====
The second secret level, and oh dear, another boring run because of the rocket jump possibilities. I didn't spend much time here, but I'm actually happy with the way the final run looks. I guess things go rather smoothly when there isn't much going on, I just got the gold sphinxes and got the hell out. :)
Also, at the start, I pick up that health pill since a rocket jump will cost exactly 50 health without armor... so I'm afforded a second rocket jump without killing myself here.
==== Level 15 - The Great Pyramid - 5:59 ====
I skip the first arena with a double rocket jump right off the bat. Hurray! :)
Reaching the ramp of the great pyramid will initiate the countdown on the door, so doing that as quickly as possible is the idea here. Afterwards, I'm free to defend myself in any way I choose, all while shooting cannonballs clear across the landscape at the boss in the distance. The final battle could be a potential luckfest, since even if you go through the four hoops as fast as possible to zap the boss, he won't always be in the right position at the end. Sometimes he'll stay in place and use his weapons multiple times so the blast misses him entirely... grr, annoying I tells ya."