Poor abused walls !
Cant stop playing it even though ive finished it many times. I get a sudden urge and have to speedrun from the first to the last level.
The controls are very responsive and the difficulty curb the first time through was damn near perfect. Whats really addictive is that even though the basis for the game (double-jumping and wall-jumping) is simple enough if you keep playing you keep getting better in a pretty linear manner.
When you get pretty good most levels take only 10-20 seconds to beat which is just great for replay value and instant gratification.
I yearn for more levels or a sequel !