Damaging floor

Damaging floors appear in Doom, Heretic, Hexen, and Strife. They form part of the "dangerous Doom environment" described in the game booklets:
 * Slime and other radioactive waste: Many of the areas in Doom contain pools of dangerous liquids that will damage you if you walk through them. There are several varieties of waste, each doing increasing damage. If it looks fluid, beware!

Despite the damaging effects, it is often necessary to cross a damaging floor during gameplay. Crossing as quickly as possible minimizes the damage. If the player has armor, then the damage is split between health and armor. Also, the radiation suit protects the player from damaging floors for a limited time.

Monsters are not affected by damaging floors.

Technical information
The fluid appearance is implemented using animated flats. These include nukage, lava, blood, etc. Flats are also defined to implement blue water, but this is not usually damaging.

It is not the fluid appearance, however, that makes a floor damaging. The level designer assigns a special type value to make the floor of a sector damaging when the player is within the typed sector.

The following damaging floor types are found in Doom:

(Damage is halved, rounded down, at skill level 1.) Thus, there can be (and are) damaging floors that do not have the usual fluid appearance, and sometimes a floor expected to be damaging because of its texture is not damaging.

A specialized damaging floor type (11) is occasionally used in the last room of a level (e.g. E1M8: Phobos Anomaly). Damage is inflicted as with type 5, but when the player's health drops below 11%, the level ends. Play then proceeds to the next level, if applicable, with the player's health restored to 1% if it has fallen to 0% or lower. These sectors cancel the invulnerability bestowed by the God mode cheat, although the invulnerability powerup is not affected.

"Leaky" radiation suits
For the 20% damage types (4 and 16), there is a small chance (6/256 &asymp; 2.3%) that the player will be damaged during a given second even if he is wearing a radiation suit. If each of the 60 seconds is considered independently, probability theory gives the cumulative effect as:

Due to the periodicity of Doom's pseudorandom number generator, however, it can be shown that the player instead takes damage as follows:

The latter result presumably should not be accepted at face value, since it assumes that 60 numbers are pulled from the table consecutively, whereas in a real level, other phenomena (such as roaming monsters and blinking lights) would sometimes call the generator as well. Moreover, in stock maps, it is rarely necessary to remain on the same damaging floor for 60 seconds. Testing seems to indicate that a single suit rarely "leaks" more than once.