Just right
There was a minor glitch on the first level I found, that if you jump on certain spots at the far right hand side you'd warp above everything, and if you kept holding right, you'd never fall.
Overall I'd say that the difficulty level of the game is so wonderfully ballenced, I was actually grinning at the challenge of level 3, even though I failed.
I would really love to see a second game of this with a few more levels and perhaps a continue function.