SEN.TUR.

Aliens are invading and its up to you to defend the planet. Defeat enemy aliens with your low orbit defense turret. The more enemies you defeat, the stronger they become in this endless assault. Defeating enemies is rewarded with points which you can use to upgrade your turret. The turret is composed of 4 major parts: the Chamber, the Action, the Barrel and the Modifier. Each part adds a unique effect to the projectiles. Good Luck and Godspeed.