Harkens back to Old-School era gaming!
The closest 'experience' to this game I can think of is Geometry Wars. It's one of those games you don't think you will like but once you actually play it, you can not stop. It's premise is simple yet addictive. Your job is to rid Darwinia (a virtual world) of a nasty virus and save it's inhabitants named appropriately....the Darwinians. You are able to 'call up' various programs (you can even do so by making specific gestures with your mouse) and then must strategize how to rid the virus from a particular area. The virtual world's creator works along with you upgrading your programs abilities as you progress through the game.
It's is so hard to describe but for what you can pick this title up for ($10 in my case) it is well worth it for a different, innovative, and enjoyable experience.