A very enjoyable game! The jumping was really satisfying and the gameplay was quite fast paced, which I personally like. The only problem I had with jumping was that it wasn't always that clear whether or not you could jump in some small space. Of course you would find out by clicking, but it was mildly unsatisfying.
Otherwise it was quite fun hopping through the game. The boss fight was fun and unexpected :)
Also, you can jump out of bounds in the tutorial by going up right from the room after the first enemies :)