The slide in the Sales and Special Offers section of the marketplace says "35% off today only", so don't delay! This is the first game, not the sequel.
http://marketplace.xbox.com/en-US/Product/Star-Wars-The-Force-Unleashed/66acd000-77fe-1000-9115-d8024c4107d2
http://marketplace.xbox.com/en-US/Product/Star-Wars-The-Force-Unleashed/66acd000-77fe-1000-9115-d8024c4107d2