Level 1 (House) not too bad
Level 2 (Halloween?) the blade you guy you just need to wait.
Level 3 (Platforms) I just fluked it.
Level 4 (Pit of Death) is pretty fun.
Level 5 (Space travel) is easy, but keep to the L of screen after the first few batches of apples and avoid the Moon.
Level 6 (Stace Station) pretty simple once you figure out the gist of it.
Level 7 (Gravity Factory) dead easy
Level 8 (Video Games) pretty straightforward though i did start looking at InvisibleSoul's walkthrough to save some time at the Donkey Kong section.
Level 9 (Spikes/Random stuff) Not too hard but took a while to figure out those alternating spikes, and couldn't find a pattern to that upside-down volcano.
Level 10 (Black + White) A bit tricky, all about getting the timing right.
Level 11 (Boss) read the walkthrough for that one.
Woohoo, beat the game, only took 8h and 825 deaths!