Moonshot Games is a studio formed by ex-Bungie folks who are working on a side-scrolling shooter. And, according to the Internet's own Sam Houston, there's a smidge of ex-Harmonix action going on at the company now, too. The game is named Fallen Frontier, and attached is the debut trailer.
They're offering up a few more details here, on the official site. For PAX East attendees, look for booth #759 stuck between Haunted Temple Studios and Robot Entertainment. Sounds like a happening spot to me.
Jonathan Ross urged me to reference the old run-and-gun Abuse for serious nerd cred, but I don't know what that is. Partial credit for trying?