This week Xbox 360 owners will be treated to a double whammy on Xbox Live with Sierra Online’s Arkadian Warriors and Sidhe Interactive’s GripShift. Both games cost 800 Microsoft Points each and will be available on Xbox Live Arcade tomorrow.

In Arkadian Warriors players will choose to fight as one of three shape-shifting heroes of Artemis (a Solider, Archer or Sorceress) to save the goddess Artemis and the Land of Arkadia from evil Gorgon. Each warrior has unique fighting and shape-shifting skills (Phoenix, Lion or Dragon) and players must build these skills and upgrade their inventory as they progress to sharpen their skills, gain more powerful magic and weapons as well as stronger defensive units.

The game features randomly generated dungeons (so you will never battle in the same dungeon twice) as well as a two player cooperative multiplayer mode both locally and over Xbox Live.

GripShift features 120 single player challenge mode levels, 25 race mode tracks and 20 deathmatch arenas in four different worlds. You will need to collect power-ups, avoid traps and combine your racing and puzzle skills to conquer this mix of platform gaming and stunt driving action. Players can play the game either solo or with four players over Xbox Live. Racers can customize their music and ride, choose their driver and unlock faster cars.