Complete the following achievements to unlock Xbox Live Gamerscore points:

Armory (10 points)         : Collect gout different weapon power-ups.
Bulletproof (25 points)    : Complete the game in Arcade mode using only 1 credit.
Full Assault (30 points)   : Complete the game in under twelve minutes.
Infiltration (15 points)   : Destroy the alien tower at the end of the water level.
Partnership (20 points)    : Complete the game in Xbox Live Co-op mode.
Proficient (20 points)     : Complete the second tunnel with a score of 100,000 or more 
                             in Arcade mode.
Team Work (10 points)      : Score 100,000 points in an Xbox Live Co-op game.
Tunnel runner 1 (10 points): Beat the first timed tunnel with 33 seconds or more left.
Tough Guy (20 points)      : Get to the second tunnel without obtaining a single weapon 
                             upgrade.
Tunnel runner 2 (15 points): Beat the second timed tunnel with 55 seconds or more left.
Untouchable (10 points)    : Get to the first tunnel without losing a life.
Well Equipped (15 points)  : Collect three different weapons in the second tunnel