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

Cadet (5 points): Complete a game of Dogfight.
Hero (10 points): Earn gold medals on all Defense Missions (Headquarters, Big Guns, and Reconnaissance).
Professional (10 points): Earn gold medals on all Assault Missions (Bully Fight, Zeppeligeddon, and Bombs Away).
Technical (10 points): Earn gold medals on all Navigation Missions (Ring Race, Birds of War, and Follow the Leader).
Big Guns (15 points): Earn 100 kills from the Turret.
Flawless (15 points): Complete any mode with 20+ kills and no deaths (Multiplayer Only).
Helping Hand (15 points): Earn 250 assists.
Sky King (20 points): Earn 25 wins (Multiplayer Only).
Weaponeer (20 points): Earn 25+ kills with every secondary weapon.
Classic (25 points): Earn Doghouse reward 10 times (Multiplayer Only).
Veteran (25 points): Earn 10,000+ points (Xbox LIVE Player Match Only).
Flying Ace (30 points): Reach Flying Ace Status (Xbox LIVE Player Match Only).

The following achievements require the "Suppertime Of Destruction Pack" bonus downloadable content:

Bully (15 points): Kill any Blockhead (Xbox Live Player match only).
Camouflage (15 points): Survive 5 minutes with no deaths (Xbox Live Player match only).
Kite Flyer (20 points): Get 50+ kills for both "Kite" class airplanes (Dragonfly and Whirlybird).