From the submission comments: It's Commander Keen 3! Released in 1990, this is the final game in the Vorticon trilogy, using the same engine as Keens 1 and 2. This time Keen must face the Grand Intellect, an evil leader who enslaved all Vorticons and indoctrinated them with only one thought: "Keen must die!"
While there are 16 levels total, only 3 are required to beat the game. In RTA timing this run finishes in 1:37.68 and beats the cancelled run by 30.39 seconds.
If you enjoy this movie, TASVideos also has runs of all the other Keen games.