Note: This code may longer work after the latest game update. Pause the game on Xbox Live when you are low on health, then rotate the D-pad in a full circle at least three times. Select the "Achievements" option at the menu. Press B to exit that screen. Select the "Resume Game" option. You will still remain at the same screen. Select "Resume Game" again. The game will begin with your character at full health. Alternately, pause the game on Xbox Live when you are low on health, then press Guide to enter the Dashboard menu. Press Guide again to exit the menu and resume the game with full health.
Successfully complete the game to unlock all missions. Note: Using this option will prevent the "Humanitarian", "Madman", "Mercenary", "Sleuth", "Veteran", and "Combined Assault" achievements from becoming unlocked.
Accomplish the indicated achievement to get the corresponding number of Gamerscore points: