Wolfenstein 3D was a FPS game made in 1992 in ID software.

It was famous for being first popular (not first FPS, though, as ID published before Hovertank 3D and Catacombs Trilogy + 3D) FPS game

The game's main objective was walking around dungeons and killing nazis. (It was a quite original storyline, back then)

Levels of the game were built from blocks placed on 64x64 grid. The floor and ceiling was a solid color. (Mostly gray)

The full version of the game had 6 episodes, with 9 levels each. To finish episode you must kill the boss. (Except for episodes 1 and 5, where you must escape/steal plans)

The storyline goes as following:

You are B. J. Blazkowicz, American spy with Polish roots. You are mostly famous for spoiling chemical war and killing evil General Fettgesicht.

You are sent to Castle Holehammer, due to rumors of some gray-skinned soldiers seen there. Your mission: to assasinate evil and crazy Dr. Schabbs.

You were on your way, when suddenly you hear a loud "thud" and faint.

You wake up in dungeon. Soon two guards come and make fun of you. When the last one is exiting, you get knife you've hidden in your pants and stab him. Then you steal his gun. But that's not over yet. You have to escape...

That wasn't very long story, was it?