This was a tough film to watch. It's immediately uncomfortable because of Arthur's manic laugh, which comes out at inappropriate moments due to his medical condition (does that really exist?) Then the film gets darker as it goes on, and Arthur loses hope. The backdrop, which prevents it getting too miserable, is that it's taking place in Gotham City and boy batman is around too. Thomas Wayne isn't quite the hero we thought he was though.
There's a certain amount of ambiguity during the story, and as it's all told from Arthur's viewpoint, and he's an unreliable narrator, it's hard to know what to believe. It's a little like American Psycho and even more like The Machinist. Not only does the protagonist not really know what's true, he doesn't really care.
I would say the pacing is slightly off and the second half drags a little, plus the crossover with the TV show seems a little far-fetched (it feels like it's about the 1970s, so how would anyone have filmed Arthur's performance in a little comedy club and sent it to a talk-show?). Those are my only issues though, apart from it obviously being rather grim viewing. I wouldn't recommend it to many, but I'd like to see it again myself.
