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

Bail Out (20 points): Escape from a dangerous situation.
Guns Guns Guns (20 points): Destroy 5 hostile vehicles with helicopter gunfire.
Fire Hazard (20 points): Pass through an explosion and destroy the enemy.
Life Saver (20 points): Use an attack helicopter to rescue the captured pilot.
Fearsome Guardian (20 points): Protect allied ground forces with the gunship's firepower.
Emergency (20 points): Deal with an emergency situation.
Total Annihilation (20 points): Eliminate all bombers and prevent the use of a weapon of mass destruction.
Steel Hunter (20 points): From a helicopter, support the special forces while they suppress hostile vessels.
Defender of World Heritage (20 points): Provide close-range aerial support to wipe out hostile ground forces.
Hot Pit (20 points): Defend the allied base.
One Million Tons of Scrap Metal (20 points): Weave through a hostile fleet's defense and rescue the hostage.
Nick of Time (20 points): Prevent the launch of ICBMs by infiltrating the enemy base in a stealth bomber.
Berserker (20 points): Eliminate your enemies to open a path for your allies.
Patriot (20 points): Defend the capital.
Friendly Fire (20 points): Perform a risky move to save your friend.
Category 5 (20 points): Chase the enemy through a hurricane.
Guardian (20 points): Thwart your enemy's plans and return alive.
Warwolf 1 (50 points): Clear all missions.
Critical Hit (25 points): Take down a hostile fighter with a charged homing missile.
Successive Kill (20 points): Take down 3 hostiles in a row with an assault chain.
Hard Strike (20 points): Wipe out hostile ground forces with ASM.
Eagle Eye (20 points): Successfully focus on 3 targets.
Stay On Target (20 points): In a helicopter, obtain (zoom in) and destroy 10 enemies.
Diverse Strikes (15 points): Defeat hostiles with all 3 of the gunship's weapons.
Gun Master (15 points): Massacre hostiles as the door gunner.
Shot Master (20 points): Take down 5 hostiles with a direct shot.
Pursuit Master (20 points): Successfully pursue 3 enemies with counter maneuvers.
Switch Master (25 points): Successfully switch from defense to offense 10 times with counter maneuvers.
Checking In (10 points): Fly through the hotel gates.
Limbo (10 points): Fly beneath a falling chimney.
Speed Demon (10 points): Eliminate the enemy threat to fighters as quickly as possible.
Machine Gun Faithful (10 points): Use the standard machine gun to defeat an enemy.
Smooth Flight (20 points): Protect allied transports from being shot down during landing.
Bomber Master (10 points): Fly a bomber and eliminate a large number of hostiles.
Chain Master (20 points): Master the assault chain and take down hostiles one by one.
Nice Kill (30 points): Shoot down many hostile players in competitive online.
Nice Assist (10 points): Use DFM support or ASM support to join a flight member.
Nice Save (10 points): Save an ally being targeted by hostile players in competitive online.
Veteran Pilot (20 points): Play for an extensive amount of time in competitive online or mission co-op.
Warwolf Squadron (30 points): Clear all levels in mission co-op.
Formation Attack (20 points): Join the same DFM with two others and shoot down a hostile (mission co-op).
The Collector (20 points): Pilot all of the aircraft in the game.
Welcome to Mission Co-Op (20 points): Clear 1 level in mission co-op.
Aerial Sniper (20 points): Use DFM to destroy 10 airborne enemies in competitive online.
Ground Pounder (20 points): Use ASM to destroy 30 ground enemies in competitive online.
Interceptor (20 points): Use an attack helicopter and destroy 10 missiles or bombs in competitive online.
World Tour (30 points): Play on all maps in competitive online.
Ace of Aces (30 points): Obtain an A rank for every mission (free mission).
All Rounder (30 points): Obtain all MVPs.

Additionally, there is one secret achievement:

Calamity (10 points): Used Trinity to wipe out the enemy (free mission).