Key



A key is an item used to open designated locked doors or switches.

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 lost 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. In stock maps, 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 is occasionally violated, such as in E2M3: Refinery which had keycard pickups but skull doorframes.)

Keys, as other things, can be flagged to appear on certain skill levels. This allows the map designer to place a key in a more challenging spot for higher levels of difficulty. The original games include a couple of instances. In E3M6: Mt. Erebus, the blue skull key can be found quite effortlessly in the center area when playing on the easiest levels. If played on Hurt Me Plenty or higher, the key is instead hidden inside one of the buildings. Thus, in addition to being attacked by a larger population of monsters, the player also has to explore more areas to find the key. In MAP06: The Crusher, the blue keycard will appear at one of three possible locations in the great crusher hall. The more difficult the skill level is, the bigger effort the player has to make to obtain the key.

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. However, the feature was limited only to toggles that open fast doors permanently. Such switches were already supported in Doom II but the level designers never used them in the game.


 * Boom introduced door types that require the key to be of the right type and not just the right color, such as a door that responds to a red skull but not to a red keycard. Boom also introduced locks requiring all keys, a situation sometimes approximated in the original games by placing several locked doors in front of each other (e.g. E2M6: Halls of the Damned), and locks requiring any key. In Boom and compatible ports (that is, most ports), a locked door can be activated in any way a linedef can (including walkover) and can have any movement speed and delay before moving back (or staying in the final position) supported by Boom.


 * Hexen replaced hardcoded linedef types (e.g., 26 for blue key, 27 for yellow, 28 for red) by action specials where the key is represented by a parameter, making it simpler to manage the eleven key types from the game. In addition to door specials, Hexen also allows ACS trigger specials to be locked in the same manner. ZDoom extended the parameterized system to allow mappers to define new lock types with the LOCKDEFS lump, enabling the creation of doors requiring any arbitrary key combination.


 * Doom 64 changed the key system to be entirely independent of line type, instead being a property of the linedef itself. This allows to use key locks on any line type; for example there is a "locked" tripwire in MAP30: The Lair, which lowers a switch on the wall when traversed, but only if the player has the yellow key. If the player does not possess the key the switch will not lower, the marine will grunt, and the line "You Need The Yellow Key" will appear at the top of the screen. In addition, the game will make the appropriate key icon in the status bar flash for a short while when trying to activate a locked line without the proper key.

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.