In the 1976 film Taxi Driver, we watched Vietnam veteran Travis Bickle's descent into madness. It was a disturbing film, one that stayed with you long after the credits rolled. It didn't help New York City's reputation with tourists, either.
The change was that the colors of the final shootout were muted, so the blood did not look as red. There are no existing prints of the film with the original color. See the rest of the illustrated facts about Taxi Driver at TVOM.