Previously released on PSP and PlayStation 3, GripShift mixes elements of platforming, racing, and puzzle-solving. The downloadable Xbox 360 version adds a new deathmatch mode and several graphical tweaks while retaining support for four-player online duels.
Arkadian Warriors, meanwhile, is a top-down action-RPG with randomly generated dungeons. It supports two player co-op both locally and over Xbox Live.
For more on GripShift, check out Carlos' hands-on with the game, as well as his chat with Sidhe co-founder Mario Wynands about the series' future and the developer's upcoming Speed Racer title.
Haven't really heard of Arkadian Warriors before, looks kinda neat in an RPG-lite sort of way. Look forward to giving that a try along with GripShift.