The original 'trilogy' is a bit more distinct from the rest IMO; Yes the basic platforming concepts are the same, but I'd say Keen 3 and Keen 4 is a pretty subs

The original 'trilogy' is a bit more distinct from the rest IMO; Yes the basic platforming concepts are the same, but I'd say Keen 3 and Keen 4 is a pretty substantial jump in style/features like swimming. (Also setting aside the odd duck of Keen Dreams). Did anyone ever actually successfully buy just one episode? I mean, 10 year old me did from a different publisher (Epic Megagames), but they just sent the whole trilogy anyway. But overall yes, a lot of those folks got good at churning out games, and part of that was understanding the value of good tooling. The level editor used for Keen, called TEd (Tile Editor) was actually used for something like 30 different titles, both 2d and 2.5D, prettymuch up to the original Rise of the Triad..