At the "Bonus Codes" menu, enter one the following case-sensitive codes to unlock the corresponding bonus mission:

Mission Code

Ambush (North American version) AmbushU454
Ambush (European version) SATURN
Attack From The Darkness (European version) AMAZON.DE
Close Quarters CloseQ8M3
Coastal Fortress (European version) Play.com
Coastal Stronghold StrongM577
Debris Field OFPWEB2
Encampment OFPWEB1
Fire Team Engagement BLEEDINGBADLY
Night Raid RaidT18Z

Kicking doors open - While sprinting towards a locked door, hold [Use] to kick it open.

Easy "Skirinka Island Tour" achievement - In Mission 1, go to the western beach on the island. Destroy the western SAM site, then walk along the beach to find the hidden PLA helicopter.

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

Florence Nightingale Award (20 points): Apply the field dressing to other wounded soldiers 20 times.
All Patched Up (20 points): Apply a field dressing to an injured friend in co-op.
Unbloodied Hands (20 points): Complete a mission without directly killing anyone yourself.
Company Killer (50 points): Kill or incapacitate 100 enemies.
Platoon Pounder (30 points): Kill or incapacitate 50 enemies.
Squad Slayer (20 points): Kill or incapacitate 25 enemies.
The Sky is Falling (20 points): Kill an enemy with a helicopter without using its weapons.
Clear Skies (20 points): Kill an enemy vehicle with an AA weapon.
Scrap Metal (20 points): Kill an enemy vehicle with an AT weapon.
Low Blow (20 points): Kill an enemy vehicle with an AT mine.
Hard Rain (20 points): Call in your first artillery barrage.
Shock and Awe (20 points): Call in your first air strike.
Without Warning (20 points): Destroy Radar emplacement.
Saber Beats SAM (20 points): Disable the SAM sites.
Tide's Out (20 points): Successfully hold the beachhead.
Runway Relief (20 points): Capture the airfield.
Sandman Saviors (20 points): Extract the downed air crew.
Fly Away Peter, Fly Away Paul (20 points): Get to the extraction chopper.
Resource Management (20 points): Secure the fuel depot.
Heroic Rescue (20 points): Rescue the hostages.
Uphill Struggle (20 points): Eliminate the PLA mortar site.
Bug Out (20 points): Reach the extraction point.
Ship It (20 points): Assault the Naval base.
Skirinka Island Tour (30 points): Find the PLA helicopter and fly it around Skirinka Island in Dragon Rising.
Ghost Ops (30 points): Eliminate the PLA Commander in Blinding The Dragon.
Get Creative (30 points): Destroy the PLA APC at the top of the beach in United We Stand.
Hip Shooter (30 points): Destroy the fleeing PLA transport helicopter in Eagle Offense.
Hitchhiker (30 points): Destroy the PLA armored units around the ghost village in Powder Trail.
Fuel the fire (30 points): Destroy all of the PLA fuel trucks in Hip Shot.
Ruthless Efficiency (30 points): Eliminate the remaining troops on the second line with one mortar barrage in Bleeding Edge.
Perfect Rescue (30 points): All hostages must survive in Looking for Lois.
Keep 'em Rolling (30 points): Ensure all of the Abrams reach the supporting fire position in Trumpet's Sound.
Two Birds, One Stone (30 points): Eliminate Han and the radio station with one JDAM in Decapitation.
Vertical Envelopment (30 points): Pilot an MH-60S safely to the designated landing zone in Dragon Fury.
Dragon Rising (70 points): Complete the campaign on any difficulty.
Dragon Rising - Hardcore (100 points): Complete the campaign on Hardcore difficulty.