I enjoyed it, even with the rage-inducing instadeaths. It makes beating the game all the worthwhile. Level 21 was super long.
For people who had a hard time, keep your nose between 10 o'clock and 2 o'clock position, be patient, and you'll have an easier time.
4.5 out of 5 because the medals aren't showing for me past level 17 (I beat all levels).