I adore the art and animations! The concept, too, is lovely. Never knew I needed a mopping skeleton in my life, but I *did* and I am glad that now I have it. The mode-swap animation is a particular joy.
I didn't mind the number of keys, exactly — it's a little, I dunno, QWOP-y? — but the level was so short that I didn't have much of a chance to really settle into the muscle memory of immersion. I do agree with the other commenter that perhaps up/down (W/S) could be used to pick up/put down the bucket since those aren't otherwise used currently, but it's perfectly playable as-is.