Hahaha, they use scared by acid a lot in the Batman mythos, huh?
I'm glad they didn't use that for either the Joker or Dent in this film series. I love how Ledger's Joker gives a half dozen different stories about how he got his scars!
No origin story is so refreshing.
Spoiler:
Well, technically this was the origin of Two-Face its just not the focus and drawn out. It always bothered me that "origins" have to happen overnight. In DK we're told his origin disguised quite well.