Batman actually takes a little while bringing The Joker into the fold: half an hour passes before Jack Napier is cornered by Batman at the Axis Chemicals facility and ends up falling into a vat of chemicals, being presumed dead as a result. Again, though not outwardly explicit, it's pretty grim stuff for a PG-13 movie: Napier's blood-curdling scream combined with the thought of what that waste was doing to him is thoroughly unpleasant, but finally gets the movie's momentum heading in the right direction.