Fun platformer - probably has the nicest feeling jumping mechanics I've encountered so far! The lighting effects for movement and SFX for duplicating were also satisfying.
The chill music really helped me to not get frustrated when I made mistakes (well, until I duffed up and accidentally pressed M in just the wrong place right at the end of a level xD)
Some kind of checkpoint system, even only on an easy mode, might help the replayability a bit, but overall, this is a solid, fun game!