First of all, please make it "play in browser" so we do not have to download the html first.
The rules of the game are quite simple, so I would personally not put out the 4 pages of text in the begining of the game to tell the player exactly how it works.
I really don't like level 3, i don't think it adds anything for the player to learn but just forces the player to push a lot of obvious buttons. Level 1 and 2 are good introductions and then the difficulty ramps up in a good pace with level 4 and on.
Level 6-8 and 10 were interesting and required some thought from me. But whats up with level 9 coming as the second to last level and being very easy? (or maybe it is just me)
In general though, it is a fun short game. Good job!