His laughter (spoilerama)

Reading through some of the topics concerning the ending, about why the guy is laughing.

I didn't think he went mad while he watched that movie, but instead laughed because the movie has so desperatly wanted to see, was actually aweful. The laughter also felt kinda forced & it doesn't make any sense to me that one would laugh while going insane. Even heard of someone going insane while watching gruesome images? Maybe eventually desensitezed, but insane?

And he has a serious wound somewhere in his body since blood is pouring down on the ground. My guess is that he's dying anyway?

Laughing at how bad the movie is, is his final way give her the finger & win. He was a connaisseur of horror movies, so I guess his opinion actually would mean something to her.