Neat game! Could see this as a successful little mobile game. Here are my thoughts:
+Very fun core loop
+Fun art design (cool health bar idea :)
+The different build options and upgrade-stacking is fun
-The shop auto-appearing can be disruptive
-On Wave 8 I experienced a bug where my main ball de-spawned, leaving me helpless :(
Overall fun game with a lot of promise!
