Key



Keys are used to open designated locked doors.

Description
There are two types of key: electronic keycards, and "skull keys" which resemble glowing monochrome skulls. If the player encounters a locked door and attempts to open it without the correct key, the door will not open (and the player will receive a message to that effect). Once a key is obtained, any locked door of the corresponding color on the map can be opened. All keys are returned upon exiting a map.

Multiple keys of a given color may be picked up in the same level; the status bar will display whichever type was last taken. Doors in vanilla Doom are affected identically by keycards and skull keys. As a cosmetic guideline, a bar of coloured lights surround a locked door when keycards are used, while a column of coloured skulls are used for skull keys. However, this has been occasionally violated, such as in E2M3: Refinery which had keycard pickups but the locked doors were marked with skulls.

In multiplayer deathmatch games, all keys are removed from each map, and players spawn carrying all keys.

Enhancements
Ultimate Doom and Final Doom introduced "locked" switches, which cannot be activated without a key of the appropriate color.

Boom, introduced door types that require the key to be of the right type and not just the right color. Such doors are supported in most source ports.

Certain source ports also allow the use of locked doors requiring multiple keys, an advancement over the original Doom engine which often placed several locked doors in front of each other such as in E2M6: Halls of the Damned.

Data






Appearance statistics
The IWADs contain the following numbers of keys: Blue keycard

Red keycard Yellow keycard

Blue skull key Red skull key Yellow skull key

Doom RPG
Keycards appear in Doom RPG, but skull keys do not.