At the very outset of the game you'll be given money to upgrade your weapons. You can exploit this. Spend the money and then play to the cutscene with the first morality choice. Quit out to the main menu during the following cutscene. Return to this campaign again and you'll have all of your upgraded weapons plus the boost in cash to upgrade again! You can repeat this indefinitely.

Complete the game to unlock Big Heads and Infinite Ammo cheats (check the Options screen afterwards). While cheats are on, you cannot earn trophies or achievements, you loser.

Have a saved game from Army of Two (the first game) under the same profile or gamer tag to unlock permission to buy the AS-KRI and Grand Pinger.

Perform the actions below to unlock additional costumes:

• Civilian costume - Beat the game on any difficulty
• End costume - Beat the game on any difficulty
• Mall costume - Beat the game on any difficulty
• Medium Armor costume - Beat the game on any difficulty
• Old school costume - Beat the game on any difficulty

Being good unlocks far fewer weapons because you're a schmuck. Opt for the negative moral choices to unlock more weapons from the get go.