The berserk pack brings your health to 100% (if you have less) and gives you a lot more strength with the fists (which automatically come up). I think it's useless, considering it only adds strength to the fists and you probably have more powerful weapons. Also, it gives the screen an annoying red tint (see above screenshot).
Blue Armor
The blue armor gives you 200% armor. It takes 2/3 of the damage and your health takes 1/3.
Green Armor
The green armor gives you 100% armor. It takes 1/3 of the damage and your health takes 2/3.
Computer Map
The computer map makes your map show the whole level. These are rare considering they reveal secrets.
Health Potion
The health potion adds 1% of health. They are usually in groups and can bring your health up to 200%.
Invulnerability
The invulnerability gives you temporary invincibility. And as far as the screen, as if making it black & white isn't enough, the colors are reversed!
