Unlock ALL Levels
At the 'Mission Select' screen hold both the Left and Right Bumpers and quickly enter using the d-pad Left, Left, Right, Right, Y, Y.

Achievements
Play a Single-Player campaign mode and accomplish a certain task to unlock these achievements for Gamerscore points.

Completed Training - 50 Points:
Complete the Basic Training Level.

Veteran of Hill 400 - 60 Points:
Complete Hill 400 levels on Veteran.

Veteran of Rommel's Last Stand - 60 Points:
Complete Rommel's Last Stand levels on Veteran.

Veteran of Crossing the Rhine - 60 Points:
Complete Crossing the Rhine levels on Veteran.

Veteran of Fortress Stalingrad - 60 Points:
Complete Fortress Stalingrad levels on Veteran.

Veteran of The Battle for Caen - 60 Points:
Complete The Battle for Caen levels on Veteran.

Veteran of The Tank Squadrons - 60 Points:
Complete The Tank Squadrons levels on Veteran.

Veteran of Stalingrad '42 - 60 Points:
Complete Stalingrad '42 levels on Veteran.

Veteran of D-Day - 60 Points:
Complete D-Day levels on Veteran.

Veteran of El Alamein - 60 points:
Complete El Alamein levels on Veteran.

Veteran of the Winter War - 60 Points:
Complete Winter War levels on Veteran.

Won the War - 150 Points:
Complete the game on any difficulty with ALL levels complete.

War Hardened - 200 Points:
Complete the game on Hardened or Veteran with ALL levels complete.