Level 9 is either broken or way too easy.
The fact the steamroller moves infront of everything but the monster seems a bit odd, but that can be overlooked.
Level 17 can be done a much simpler way than what I think you are trying to get us to do. Level 18 too (just pressing all the green things quickly).
A game very similar to a few others, but your physics is pretty good.
The centre for the point of view of the camera changes when you come out of the exit menu.. To wherever the mouse currently is.. this is annoying and should possibly be changed.
The ball should bounce at the correct angles as to where it hits on the crab.
As in, if it hits the front of the crab, the ball should go forward, not straight up.
That, or make the crab a different shape so I will know where the ball will go..
I do love the idea though, a volleyball game without bikini clad ladies.. crazy!
It's awesome until you have to call your game "Coins for iOS" on the app store because of conflicts :P