The game feels exceptional to play. I'm extremely impressed by all of the small details; the way it has a small animation when stopping its movement, the small animation for when it transitions from ascending during a jump to descending during a jump, the fact that it can't jump at all when inside a two-tile high space; all of it adds up to make the game feel INCREDIBLE to play!
I'd hate to be a broken record, but I do agree with everyone else that the lack of checkpoints does not compliment the trial-and-error punishment design.