Use towers to build a labyrinth from entrance to exit. Each tower can be upgraded 4 times. With each wave, enemies will become stronger, so use money you earned to upgrade reasonably.
Using a vast array of weaponry to defend your lab from alien invaders. Featuring persistent skill level system with over 20 weapons, 6 turrets, beautiful art and cool soundtracks!
Deploy your units to ambush the passing by enemies. Enemies will return fire so beware that your troops may be killed. Luckily, allied airplanes will fly by to assist you.