Name: Radiation Suit
Duration: 60 seconds
The Radiation Suit will protect you from the effects of radioactive or poisonous regions of DOOM's maps (but not enemy fire). Your view will turn green while the effect lasts. When it starts blinking from green to normal it is time to get to safer ground. Its effect lasts 60 seconds.
Name: Berserk Box
Duration: To end of map or death
(aka "Berserk Pack"). Raises your health to 100% and gives you a punch about half as strong as a rocket. Your screen will turn red for 30 seconds. Its effects last until the end of the current level (or you die). If you have a chainsaw, you can toggle between the chainsaw and berserked fist by typing "1". Not included in the shareware version of DOOM.

Note: You can continue to pick up Berserk Boxes as often as you find them. Their effect is not additive.

The term "berserk" is derived from Viking warriors called "berserkers" who wore bear skins and would rush into battle with almost superhuman ferocity.

Name: Backpack
Duration: Until you die, end of Episode (DOOM)
Doubles the amount of ammunition you can carry for each weapon and comes with ammunition for each weapon (see chart below). This items effect lasts until you die or end the game (DOOM 2) or Episode (DOOM). You can pick up as many as you find. Effect is not additive.
Ammo Included: Type       Skill 1   Skill 2+
               Bullets    20        10
               Shells      8         4
               Rockets     2         1
               Cells      40        20
Name: Computer Map
Duration: Until end of map
Shows you "all" the lines in the current level when viewing your automap. Walls that you have not yet "seen" will be gray, all the rest will be displayed as normal for the map mode view. Its effect lasts until the end of the level.

NOTE: There is a setting for some lines that will prevent them from showing up with the Computer Map (the IDDT cheat code (qv) overrides this).

Name: Light Amplification Visors (Light Visors)
Duration: 2 minutes
Light Amplification Visors raise the light level of everything in sight to the maximum (255). Effect lasts 2 minutes.

The Light Visor works by turning off the DOOM engines light diminishing code. The effect is that the entire scene is rendered as if all sectors had light values of 255 and that light does not dim with distance.

Part of the way that the DOOM engine give the perception of depth is to slowly dim the light value of the environment as the distance between the players point of view and the observed area increases. You can see this as the horizontal banding on the ceiling at the very begining of E1M1 in DOOM.