Art and sound are on point. Gameplay generally also felt good; the yoshi jump helped correct some mistakes I made which felt fantastic.
Couple of minor issues;
Early on theres a part where you can bump into an enemy the instant you warp into the area. That felt pretty awful, so you might want to make sure that enemies can't wander too close to warp points.
It wasn't really terribly clear what levelling up did? The first level added more range and damage and then it didn't feel like the second level-up did anything.
Game is a little short right now and the final boss while silly is pretty much just a dummy (who for some reason never finishes dying). Not sure why the debug text is in there, either.