Freebie with this month's GWG, this is superb. You could probably play it on your own, but I've been playing it with my son and his friend co-op for an hour (same room, not online - unsure if online is available - kids are playing Rocket League now so can't check).
It's a 2D spaceship game - the ship is giant and you control the ship and the shield and the various gun turrets, map room, rockets, etc. via pods inside the ship - you literally have to run around inside the ship, changing positions depending on what direction things are attacking from. All the controls are slightly different in style so you have to switch your thinking with each role. Very cool.
Presentation is super cute and had us laughing quite a lot.
Get it now.