Is the Joker a great movie?
In a word No! Bye.
Okay i'll give you a better explanation and of course this is just an opinion (I'm not sure if they've outlawed those yet).
Joker is a fantastic movie don't get me wrong, I really enjoyed it and understand it's message because it's one I've thought about myself in recent months. But I just felt like the film had been hyped up so much that it was always going to be a disappointment.
Yes this film has done something different with a comic book movie, it's your classic art house movie. But most of it's story tropes are taken from 'Taxi Driver' and "The King of Comedy" I suppose it can be argued that the Joker is a homage to Martin Scorsese however it just takes a few to many tropes from those movies to really be original.
It's director Todd Phillips "what if?" movie the what if being what if Martin Scorsese made a comic book movies (Scorsese was originally attached to the project). The acting performance is second to none and Joaquin Phoenix performance as Arthur Fleck (The Joker) is award worthy.
The message of the film is very clear, what happen when society degrades and we stop caring about each other, when we're all alienated, answer is it breeds mental health problems and psychopaths.
I totally understand the ending is very ambiguous because that's the nature of the Joker character he prefers his back story to be "multiple choice" and whilst some fans walked away from this film thinking what was the point of sitting through this film if none of it actually happened and it was all in one mans head.
But for me what really let's the film down in my opinion is that I've seen better films. I've seen better comic book films. The best example to compare this film against is 'Logan' another art house comic book movie and yes it's a very different film it's just for me more impactful, it uses it's characters in better ways and has a better overall story.
Logan is a film that like the 'Dark Knight' trilogy I will happily watch over and over again, but Joker once is enough for me.