This achievement is for completing the game (all 15 missions) on Inferno difficulty. This is quite a challenge compared to Hard difficulty, but with the following tips this is more than doable.
Don't attempt this difficulty from the off. You really need to level up your character first by playing through the game on both Normal and Hard difficulty first.
This achievement can be done in Single Player, Multiplayer, or a mix of the two.Reach Tier 8
When you earn 793,500 xp for a class you will be rewarded with the Pesticide gun. This is essentially a nuke gun. Each of these weapons will produce 500,000 damage points upon enemies. Larger enemies (Small Hectors, Bomber Spiders, etc.) will all die with just one shot. WARNING: This weapon has a huge blast radius and will team kill any player within its range.
I strongly recommend using Rahszhul2's
guide for reaching Tier 8 to unlock the pesticide gun:Perfect the Roll
Learning when to dodge is one of the most important skills in this game, especially on Inferno. Knowing when to roll (RB) should become second nature to you. Small Hectors will deal devastating damage to you if you fail to dodge their missiles.Know when to heal
Picking up health kits is all well and good, but only if they benefit the whole team. If everyone has full health then ignore health kits. Picking one up will only give you a small amount of armour. If every player needs healing then that's the time to pick one up since all players will recieve health from it - not just you.Team kill - that's right!
I don't mean just go around deliberately killing your team mates. If a player is on a small amount of health and there are no health kits around - that's the time to kill them. Example: A player is on 50 health. Killing and reviving them will bring them back with full health. Doing this between objectives when there are no enemies around is the best time to do this.Stick with your team
There is no point in being a lone wolf. Sticking together will ensure players can be revived almost immediately. If a player is killed on the other side of the map to you, then this could be a disaster.Active reloading
Much like Gears of War, you can reload in half the time by pressing the X button when the white line crosses the middle white line. This is common sense, but it can save your life at times.Don't stand still
Constantly be on the move. Standing still is just another reason to be killed. Sprinting (LB) and rolling (RB) will be your two greatest manoeuvres in the game.Keeping your distance
When you have to face a large amount of enemies, pick them off from a distance. They can't hit you but you can hit them. This works especially well for taking out Ant hills. Stopping the flow of ants from a distance before actually destroying the hill will make things much easier.Kill ticks
In my opinion, these are the most annoying enemies in the game. If they jump on you and explode it will deal some 500 damage! You must be ready to smash the Y button to remove them if this happens. I always carry a machine gun or shotgun to make quick work of them whenever they spawn.Play co-op
Let's face it - the AI in single player are awful. Lame guns, friendly fire etc. Playing the game over Xbox Live is the way this game is meant to be played. Each player will be bringing their own weapons which will be just as devastating as yours. When facing larger enemies, work together. Have one player focusing on the smaller enemies, while the other two focus on the bigger ones.Have fun!
Don't get frustrated! If you can't finish a level then skip it. You can always play it at a later stage. Take brakes from playing as well. Playing on Inferno for too long will just drive you mad!If anyone else has some tips then feel free to post in the comments and I will give you credit.Please comment if you vote negatively. I will edit my solution to make it better.