This game is relatively entertaining and I would have given this 4 stars if not for certain peeves that really irked me.
-Glitches Galore-
This game has quite a number of glitches. The ones that I have experienced are: Tesla died after I bought an upgrade/new unit; The game froze after I bought an upgrade/new unit; Units refuse to function as it should (Son of a . . . Turkey and Chicken. . .)
-Unclear Statistics for Units-
No description of how units work; Unclear upgrades (Upgrades bought with money and stars, both of them are unclear). To elaborate on the second point, the doctor robot has an upgrade that [Heals 4 units]. How does that work? 4 units to the left or to the right? Or is it 2 on each side? Although I figured out it was the latter, the icon for the upgrade is kind of misleading :/
Tips for the game:
1) Seriously all you need are the 3 Tunguska Towers and 2 Doctor Towers, all the rest are kinda obsolete. Even the secret ones.
2) If your game ever froze (your units just gliding and enemies frozen) rearrange your units, if all else fails, usually I put Tesla all the way at the last slot. That did the trick in my experience.
Game graphics are nice, acceptable music and sound.
Judgement: Heck, try it. If anything, those easy to earn medals look good on your profile (assuming you have an account) Have fun!