http://en.wikipedia.org/wiki/Black_Crypt
Typical bard's tale affair for the Amiga (but I'm sure there must have been a PC version, i just remember it on my Amiga), this game is notable to me as probably the first game that scared the bejesus out of me when I was about 12. It was also notable (as mentioned in the above wiki) because it was possible to encounter the first end-of-level boss within a minute or two of starting the game. If you knew where to look.
The whole "4-player party forward, backwards, left or right" RPG-scene on the Amiga just passed me by, I wouldn't get into RPG's until the Elder Scrolls on PC but Black Crypt was the exception.
It's was also the first game ever developed by Raven Software.