This cheat will give you Unlimited Batarangs (if you are into that sort of thing)

Unlimited Batarangs - Batman: Vengeance

Here’s the Cheat:

• Main Menu, press:
  • Left Trigger
  • Right Trigger
  • Left Trigger
  • Right Trigger
  • X
  • X
  • Y
  • Y
• During the game, the number 99 will appear next to the Batarang