Not a fan of the controls. In a precision platformer, I want to be able to make adjustments to my jumps in mid-air, even switching directions — here you're forced into horizontal jumps of indeterminate distance if you try to add a little movement to a vertical jump, and there's no way to back out of a jump.
When combined with the lack of checkpoints (as far as I could tell), it can make for a pretty frustrating experience.