The game is a fan-made demake of Episode 1, "Knee-Deep in the Dead" (E1M1–E1M9), in two versions:

- 48K: a multiload tape. E1M1 is part of the program; the other levels are loaded from tape when you reach them.
       Sound effects play on the beeper.
- 128K: everything is loaded at start-up. All levels sit in RAM bank 3, and there is AY music for every level.
        Three levels have extra floors connected by stairs.

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Controls and cheats

| Key               | Action                                      |
|-------------------|---------------------------------------------|
| Q / A or 7 / 6    | Forward / back                              |
| O / P or 5 / 8    | Turn                                        |
| Z / X             | Strafe                                      |
| SPACE or 0        | Fire                                        |
| ENTER or E        | Use (doors, secret walls, switches, stairs) |
| 2 / 3             | Pistol / shotgun                            |
| M                 | Automap                                     |
| Kempston joystick | Detected automatically                      |
| IDDQD             | God mode (on/off)                           |
| IDCLEV            | Finish the current level (as a normal exit) |
