Nice start- especially for a first effort. A few suggestions:
Make the selection box for the towers bigger- maybe the box instead of the symbol? Make the mobs come in faster- and also, label the wave numbers in the little color box there- it took me forever to figure out how to advance the next wave. Good start, with some tweaks it could be VERY good.
Not a new concept, and am quite sure it should be flagged for content- Pinnochio is used, and that's Disney, as well as the inappropriate stickmen. in the
While it is an interesting concept, the mouse lines disappear too quickly, and the balls drop way too quickly to start with. Neat concept, but not a fav.