The game is garbage no wonder Microsoft made it free for download to make up for the weekend xbox live was down...
However, the when you determine that the gameplay is frustrating, boring, single player is ridiculously hard in later levels, multiplayer as of right now is dead, there is practically no plot, and playable units are uninteresting and no matter how many times you upgrade you are still extremely weak and die in seconds. Additionally, controls are extremely loose. You control the movement of your character in the ocean with the left thumb stick, and you shoot with the right trigger. The reaction times with the thumb stick are way to loose and tough to control.
Spend your Microsoft points on another game and spare yourself from this disaster of a game.