Dungeon levels are stored on an 8×8 grid. They loop at the edges. Each tile is stored in four bits as follows:
| BINARY | TILE |
|---|---|
| 0000 | empty |
| 0001 | magical barrier |
| 0010 | illusionary wall |
| 0011 | wall |
| 0100 | door |
| 0101 | locked door |
| 0110 | 180 rotate pad |
| 0111 | banner |
| 1000 | stairs down |
| 1001 | poison field |
| 1010 | stairs up |
| 1011 | lightning field |
| 1100 | pit trap |
| 1101 | flame field |
| 1110 | falling rocks |
| 1111 | sleep field |