Wolfenstein 3D made the FPS genre known to the world, Doom raised the quality bar and the popularity of First Person Shooters. Then came Heretic, a fantasy version of Doom with the addition of an inventory. Heretic was one of the few FPS I actually finished (and loved). I never managed to finish Hexen, but I remember it fondly, expecially the choice of character class.
1994DOSDeveloper: Raven SoftwarePublisher: id software
1995DOSprotectedDeveloper: Raven SoftwarePublisher: id software