You'll need to keep your wits about you if you're going to achieve a decent score in Tetraform, a tactical defence game from the brilliant minds of Tyler Glaiel and Greg Wohlwend. It's your job to protect 'that geometric thing in the middle' by selecting enemy ships and crashing them into each other, while building up your planet with powerups.

It all starts off nice and simple, with only a few different types of baddie attempting to plant themselves firmly in your atmosphere, allowing you to experiment with crashing certain types of craft into others. Soon, however, all hell breaks loose and you'll need to plan which ships to attract together quickly before they get too close!

Other defences are supplied, including huge spike rods for taking down pesky ships which just won't die, and a nuke for clearing the screen. All in all some good, hectic fun. Play it over at Newgrounds.