Fun game to play, although I didn't really get how to play at first, so a tutorial or a bit of text explaining would have helped a lot. This can be tough to implement, so I don't blame you.
I don't know if it was intentional, but for me what really works is that the fun beach music fades out after a while and all you hear is the death and destruction you have caused in the form of the turret sounds. It sort of brings it into a different perspective that's really cool.