Fun and simple
Pretty fun, neat idea, and nice graphics. Simple, but enjoyable.
One major problem; wall climb doesn't seem to work at all. At least, I never saw it do anything.
Also, a minor problem (which I'll spent most of this review on, naturally =]) is that double-jump is activated by holding 'jump'. Probably intentional, but I found it annoying. I never held 'jump' to double-jump, and I doubt many players do. My reasoning runs along these lines; a normal jump will get you past any single obstacle. The only time you would double-jump is if your first jump put you in danger of a second obstacle--so, double-jumping is always a decision you reach after your first jump failed. Players are unlikely to be planning a double-jump when they first press 'jump', and so having double-jump activate from holding 'jump' serves only to irritate those players (like me) who intuitively hold 'jump' when in the air.