On Biohazard, there is a Berserk power-up past a Bio Rifle and some stairs Just before the stairs is a green button. If you shoot the green button, it will turn red. Anyone inside the Berserk room will be locked inside, and there will be green toxic waste that can kill you.

Complete the indicated task to unlock the corresponding character.

Lauren: Always select the second choice for all missions. Kill Lauren in Deathmatch in Chapter 2 of Campaign mode. Lauren will eventually become unlocked after a subsequent Deathmatch in that chapter.

Scythe: Always select the second choice for all missions. Kill Scythe in Deathmatch in Chapter 4 of Campaign mode. Scythe will eventually become unlocked after a subsequent Deathmatch in that chapter.

Matrix: Always select the second choice for all missions. Kill Matrix in Deathmatch in Chapter 3 of Campaign mode. Matrix will become unlocked after a side mission in Chapter 3 in that chapter.

Akasha: Kill Akasha in the final mission.

Loque: Unlocked after a Capture The Flag match in Chapter 5.

Damian: Unlocked in Chapter 4 of Campagin mode.

Kragoth: Unlocked in Chapter 4 of Campagin mode.

Malakai: Unlocked in Chapter 4 of Campagin mode.

On the Deimos map are orange and green looking energy/grainy appearing walls. You can walk through these as well as shoot through them. There are two of these orange walls that are circular in shape at the top of the map that allows you to reach a sniper rifle.

Play the "Eden Inc." map. The spider mine drop is on the ground floor, with a Bio Rifle drop with a ramp next to it. Go up the ramp, turn around, then jump on the next ramp leading up to reach a balcony above an open area. There are spider mines at the end of this balcony. Under the novice difficulty setting you can drop down and plant the mines in that area once or twice.

Choose multiplayer team deathmatch mode with following settings. 10 bots, instagib, "Morbias Station" map, Score limit "1", lowest Bot skill level. Play solo and allow the game to idle. You should win about half the matches.