This is one of my all-time favourite games, and not just because I wrote it. It's your basic D&D style game, but more action-oriented. Nine levels that get harder as you go along, 8 kinds of monsters (each in two variants), objects, spells, an oracle, all the usual stuff. And all in a mere 16K of very compact Z80 machine code. Considering it's interrupt driven monster-move system, it's amazing it runs in ZX Emulator, albeit sometimes a bit choppy compared to a real ZX81. Also download YM-DUNGN.ZIP which lets you design your own dungeon layout.