It starts well. But the last third is really weak IMO, it's some juvenile revenge fantasy and then the protagonist is called a hero and gets the girl. I'm not sure that there is any irony there. I was disappointed. Scorsese became better after that.
There surely is! This scene is so over the top, it is clearly not meant to be taken literally. Some people even interpret it as a hallucination by Travis while he is dying.
