Joaquin Phoenix performance is intense and wholly believable. Frances Conroy is excellent as well. Brett Cullen threatens to steal the show, his Thomas Wayne is truly despicable and does humanize Arthur Flecks transformation to Joker. The social commentary aspects tacked on towards the end felt forced but Phoenix carries it off. DeNiro kinda mailed it in, but that's a package I will always accept postage due upon. It's a true slow burn that does build and the final act does rachet up the stakes to carry this over the top. Also some really great cinematography. On first view a really good film, one which could well reveal deeper rewards as time passes.