Accomplish the indicated achievement to get the corresponding number of 
Gamerscore points:

Prototype Pilot (5 points): Complete Level 2 on any difficulty. 
Combat Pilot (10 points): Finish Solo game on Normal. 
Flight Commander (20 points): Finish Solo game on Hard. 
Squadron Leader (10 points): Finish Co-op game on Normal. 
Ace Wingman (20 points): Finish Co-op game on Hard. 
Earth Defender (10 points): Earn 5 Stars on any level, on any difficulty. 
Alien Eradicator (10 points): Earn 5 Stars on all 25 levels on Normal. 
Hero of Vanguardia-7 (35 points): Earn 5 Stars on all 25 levels on Hard. 
Communications Officer (10 points): Complete Level 5 in an Xbox Live Co-op 
match. 
Scourge of the Skurgians (20 points): Achieve 10,000,000 points. 
Survivor (20 points): Complete 5 Levels without losing a life. 
Invincible (30 points): Finish game without losing a life.