Space Jammers is a 1-4 player co-op SHMUP Rogue-like full of action, loot, and plenty of geek-culture references. Each level is a dimension with its own rule-sets. As a matter of fact, everything from the missions, bosses, weapons, and gear are randomized.
Looks like it will be a great game to pick up and play with friends. You can view the Steam store page here if you want to learn more: http://store.steampowered.com/app/471400