Challenge x50 (20) Defeat 50 opponents in Challenge Mode
Combo x2 (15) Kill 2 opponents in rapid succession
Combo x5 (20) Kill 5 opponents in rapid succession
Complete Mission Mode (20) Awarded for completing Mission Mode
Completed Training (10) Complete the Single Player training mode with any character
Marksmanship (25) Score over 10,000 in the 'Shooting Range'
Played 100 Matches (25) Play 100 matches either offline or on Xbox LIVE
Six Degrees of Small Arms (0) Play online to 'catch' this elusive Achievement
Won 10 Matches (10) Win 10 matches in Single Player or by playing on Xbox Live
Won 100 Matches (25) Win 100 matches in Mission Mode or Battle Mode
Won 50 Matches (15) Win 50 matches in Single Player or by playing on Xbox Live