wpoeit

http://www.freewebtown.com/wpoeit/keen.html

The first Commander Keen series. While not as popular as its sequel,
this game nonetheless opened the door to making ID Software popular
even in the early days of computer gaming back in late 1990 - early
1991. This is just about the only Apogee game where each episode is
actually unique unlike most other games where each episode looks all
too familar with just a few shifts in the mazes. Here, besides the
mazes, each episode has its unique set of difficulties, challenges,
gameplay, graphics, creatures, missions, and even some change in
structure. You can check out each episode at the Downloads section and
enjoy the game.