Doom v0.4

Doom 0.4 was an alpha version of Doom released to testers on April 2, 1993. At this point in development, a number of elements had already been completed, and it appears that the main features of the renderer were already in place.

Version 0.4 included the following features:


 * A spinning 3D title screen, which was removed before the release version of the game.
 * The engine could render areas with different floor and ceiling heights, textured walls and ceilings, and different light levels.
 * Prone feature (removed from final version)
 * Collision detection was performed against the walls. However, there was no collision detection with sprites (e.g. monsters).
 * Monsters appeared in some of the levels. Although they were animated, they did not move or react to the player or to other monsters. Early versions of the Lost Soul sprites were included in the WAD file, although they did not appear during play.
 * The player's weapon bobbed during movement and could be fired, although it had no effect on the environment or monster sprites.
 * The game included a basic, but non-functional, status bar.
 * Doors (but not any other moving sector types) work and can be opened with the alt key.

Levels
Version 0.4 included 13 levels, some of which evolved into levels used in Doom:


 * Level 1: E2M7 (Spawning Vats). Unlike registered Doom the level has no Hell textures and is designed to be like "Hangar 2" in the Doom Bible. The Blue keycard room is a hangar with the number "2" near the center of the room and an electric track running through the center of the room. The ground floor has large crate room with only three or so crates and an exit, corresponding with the Bible's description of the ground floor.
 * Level 2: E2M2 (Containment Area). Again the level has no Hell textures, unlike the final version. It seems to be based off of "Supply Depot 2" in the Doom Bible, as it has a crate maze on the ground floor, a maze on the second one and is the level after Hangar 2, which is E1M1 in the alpha. Ultimately the level became "Containment Area" in registered Doom.
 * Level 3: Ultimately became E2M3 (Refinery) in registered Doom. The Refinery is the earliest level made by Tom Hall; Doom design was still in "Wolfenstein mode" with mostly 90° angles and little or no use of the Z axis.
 * Level 4: Became E1M7 (Computer Station) in registered Doom.
 * Level 5: The level became E1M6 (Central Processing).
 * Level 6: The level was not used in the final game; it is merely a starting slate made by Tom Hall.
 * Level 7: In retail this level became Command Control (E1M4). The level is based off of "Enlisted Quarters" in the Doom Bible, as there are lockers and showers on the left and right entrances.
 * Level 8: Became E1M2 (Nuclear Plant). Was known simply as "Power Plant" at this stage, straight from the Doom Bible.
 * Level 9: Ultimately became E3M3 (Pandemonium). At this point in development the level has no Hell textures. Ended up as Pandemonium. Could be based on the Lab in the Doom Bible, as a sign on the left side says LAB, while the right side, with a sign pointing to WH1 (Warehouse One), leads to a dilapidated area, which only makes sense if it were the "old building" section of the Lab. The two holes in the wall on the left and right sides of the stairs appear to be guard posts, as they have large red hands under them. Was to be the hub of the monorail transportation system, with the left corridor leading to the Laboratory map and the right corridor ultimately leading to the Warehouse map.
 * Level 10: Possibly Deimos Lab, E2M4. However, this level was designed by John Romero, whereas Deimos Lab was created by Tom Hall.
 * Level 11: Designed by Tom Hall. Was meant to be the "Warehouse" reachable from Level 9, but was not used in the final game.
 * Level 12/13: Mentioned in the accompanying documentation, but were not actually included.

Strangely, an aerial view of all the 13 levels can be seen in the intermission screen of the next Alpha version (Alpha 0.5).