Great game but very glitchy. The regeneration rate of towers does not always work. I had a fully upgraded tower sitting at 1 while the rest of my towers were regenerating. Slow and inactive towers make the higher levels nearly impossible to complete. Because of this glitch I give the game 3.5 stars due to the immense frustration it causes, otherwise I would give it 5 stars. It is a fun game but needs tweaking.