Cant find a picture so try this one:
It was released on the Acorn and the BBC. If featured upto 4 players who had to descend 22+ levels to recover a chalice. It was a fantasy based game, possibly the first true multiplayer game.
the company who created it had the initialy BB.
You could be a warrior, and elf, a barbarian or a wizard. There were traps, and rebounders etc around each level.