I love this game... not too easy, but not too hard either.
I just had one little problem. I couldn't get through lvl 21, so I figured... I'd use the walkthrough (yup, I'm that kind of guy) in there, it uses the disintegrator ball to destroy the block, holding the green blocks, easy win. but for some reason... no matter how or where I shoot on that block, with me, it doesn't disappear.
so I don't know if it's a bug or something... but yeah, that was kinda annoying, because now I don't know how to finish the level... I basically tried everything.