Tower Defence: Space Ship 2

A classical Tower Defense, a space ship have crashed in the Clash of Orcs lands

Space, the biggest amusement park. I was with my buddies doing ship free fall on a strange planet with some green bugs. And then the incredible have happen, not that we crashed this sometimes happens, but the green slime bugs are trying to invade the ship! So help me set up some turrets to defend the main computer and the engine core room until we can fix the ship or we can get some help.

Aggressive target in line of sight, eliminate targets in 5, 4, 3, 2, 1

GO