It feels very good, judging by my very limited platformer experience. The ass kick description should probably mention to hold the jump key, it wasn't obvious for me.
Maybe a bit too difficult in general? (I'm pretty bad at these kind of games so maybe not.)
Ah, also the rocket jump could be more forgiving, first two tries it didn't trigger for me as I shot the rocket too late (following the standard logic of not shooting oneself in a foot with an armed warhead.)