To defeat this international terrorist and assassin at the end of the game you must first defeat ALL of the ninjas that are around him or he will not die. When Ra's Al Goul attacks you with his sword try to counter the attack.

Unlock the following by completing the corresponding

2 Batmobile missions:
Beat the game once

Everything in Gallery of Fear:
Beat the game once

Caped Crusader Costume:
Complete the game on any difficulty

Dark Knight Costume:
Complete the game on any difficulty

World's Greatest Detective Costume:
Complete the game on any difficulty

All Movies and Interviews:
Beat the game once