Game: Wanderlust: Rebirth
Genre: RPG (co-op!)
Developer: Yeti Trunk
"Wanderlust: Rebirth is an online 4 player co-op retro arcade-action RPG. Wanderlust: Rebirth offers more content than most professionally-funded games including story and survival modes, online high-scores, over 40 enemies types, 15 boss battles (including 4 secret bosses), over 50 unique skills between 4 uniquely crafted character classes, 3 different difficulty modes, 3 different endings, AND MUCH MUCH MORE!"
I got this in a GG bundle last year and pretty much ignored it, but I've been hearing much about it of late. The online co-operative RPG is a rare thing, so this is definitely probably worth checking out.