Fun and good - NO IMPOSSIBLE LEVELS, I ASSURE.
Seriously. Why there is people who wants puzzle levels WITHOUT puzzle?
The main oibjective of the game is to force the player to think in a way to get the damn pothead into the green eyed blob. And there is NO impossible levels (Actually only one of then is quite hard, but nothing thinking out of the box can't cut).
I am reviewing only after beating the game, so I can say it. (If someone wants the solutions, I could give it, not here). LVL 19 is easy, since you discover that RED BLOCKS aren't solid, unless you hit the red button (Inverse of the green ones).
So the negative points (for a puzzle of course) is the very simplicity of design, what means "no challenge", but not at all. The harder, the best. It is not an allusion to pixel-hunting, nonsense solutions or lucky-dependant games.