Radian Guard provides pure arcade gameplay, taking inspiration from invaders and arkanoid while introducing unique elements to the mix. You control the lone defensive system of the Core. Armed with a strange ball, your mission is to protect it from enemies bent on it's destruction. Defend against them in 90 levels across 6 areas and be mindful, as the further you get the more tricks they have up their sleeves. And if you feel like challenging yourself, try out the Horde and Target modes.

http://armorgames.com/play/18445/radian-guard