Ace Difficulty...
	Games for Windows Live Achieve...

Ace Difficulty is a hidden difficulty mode. In Ace, health regeneration is removed, and enemies are stronger. To unlock, complete campaign mode in Elite Difficulty.

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