Crimson Dragon has been updated with an anticipated multiplayer mode, among other goodies.
According to PlayXBLA, the other major addition of the patch is a new difficulty level, Insane.
Otherwise, the content of the 4GB patch seems to be mostly fixes.
Crimson Dragon is a Kinect-only title for Xbox 360 and Xbox One, from the creator of Panzer Dragoon. It's something of a spiritual successor to that title. Reception seems to have been mixed, but Grounding is hoping to make an RPG set in the same world.