For those who don't know, it's made by id Software : https://en.wikipedia.org/wiki/Id_Software#Commander_Keen
Revelation: Today, it's amazing to me to have a 128GB ssd on my keychain.
I played Keen exclusively with a joystick for years and was pretty good at it. If you sat me down with the exact same joystick I could probably still play pretty well, but the much looser feel of a modern joystick would screw me up. When my brother and I would play Keen, we'd make the plastic on the joystick case creak from the frantic maneuvering!