Full title of this game is "Commander Keen: Invasion of the Vorticons". I thought that this game was SO amazing when I first played it (many years ago), and it's still quite fun now. It features great graphics (for EGA) and some not-so-annoying PC speaker sound effects. The jumping and pogo-sticking (yes, that's a word) take a bit of getting used to ... otherwise, a great, classic Apogee platformer.