Wizardry I : Proving Grounds of the Mad OVerlord, which RPG player doesn't know it?
Released over 20 years back in 1981, it was the first first-person dungeoncrawl, and a fine one aswell.
You had to create a party of six adventurers, and crawl your way trough ten levels of dungeon to confront the ultimate evil.
Werdna, the evil wizard.
It can be rather tough at times, since there were times I crawled back the the tavern with only one member still alive, and not even having enough money to fully heal him, letalone ressurect the others.

Review by Carpa (Lands of N'uryk)