Joker is defined solely by its influences. It wears its debt to Scorsese on its sleeve, embracing the concepts of The King of Comedy and Taxi Driver as plainly as the red nose on Joker's face.
But there's another few influences it has tried to ignore, in its ambition to be a truly great movie.
It has very good cinematography and colour grading.
It has an eclectic and funky needle drop sound track.
It has an engaging lead performance by a charismatic actor.
It has a leaden, on-the-nose script, with no depth or subtext whatsoever, with conflicted intentions about the violence it depicts, with paper thin characters, the subtlety of a brick and the air of superiority as if what it's doing is so unique, so vital and so boundary-stretching that it should be commended for doing something different for a comic book movie.
Unfortunately, every quality I listed above is totally emblematic of a comic book movie. For all the talk of this being not your grandma's cup of DC, this is through and through as vacuously entertaining, as breezily enjoyable and as thrillingly forgettable as any movie in the MCU.
Let's start with the lead performance, because that's where much of the attention is. Phoenix is very good in an extremely thin role, but ultimately is only offering variations on roles he's done before and done better. Fleck here is a mix of the angry anti-social Quell in The Master, the explosive Joe in You Were Never Really Here and sad sack Theodore in Her, but it's all surface work. We're told everything that is wrong with his character: family history; mental illnesses; hang-ups on friends and relationships. These are spelt out to us in Todd Phillips' script, who couldn't think of a way to communicate his ideas without Phoenix explicitly saying it to a social worker or writing it down in a journal (honestly, his lack of subtlety when it comes to third-act imagery - think the Waynes - is mindblowing). Phoenix is underserved by a character who is too pitiful to loathe in the enjoyable way we should a Joker, but too unsympathetic to pull for as an anti-hero. Compare his work here - all tics and physicality - to his work in Her or Inherent Vice; there was humanity underneath those characters, pasts and desires and sorrow and layers that were all hinted at through the extraordinary performances of its leading man. Here, it's just affectation. He dances because the script dictates he should because he's crazy and unpredictable. He smokes in slow motion because the director thinks that exudes 70s cinematic cool. It's all artifice; not once does Arthur feel real. He's a facsimile of what it probably feels like to be ill and on the outskirts of society, an amalgamation of all those feelings wrapped within one discomfortingly gaunt figure. To compare him to a Scorsese leading man, it's Phoenix's Revenant (another film whose explicit storytelling is to its detriment); a really strong physical performance which cannot match the complexity of past roles (and DiCaprio would prove with OUATIH - a gorgeous character with a performance to match - that one's best work can come after an undeserved Oscar; Phoenix deserves it far more for three or four of his past performances).
Phillips is so in love with Phoenix's performance and the character of the Joker - who has none of the charm or unpredictability of Ledger, nor the humour or suaveness of Nicholson, and not even the uniqueness of Leto's car crash to stand out - that his sympathies become very hard to decipher, and that makes for a jarringly awkward watch. All along we're shown and told that nothing is Arthur's fault: his poor luck at work down to thieving youth gangs and duplicitous co-workers; his mental illness a product of his parents; society's fault for not understanding him or his ailments. And when violence comes more frequently (for the first instance of it is more ambiguous), Phillips is too seduced by his protagonist to coax his script to adopt a more pointed stance on his actions. This is an 'eat the rich, fuck society' movie far more than it is an indictment of a super villain.
There's thrills to be had: the performances are uniformly strong (if woefully underwritten; Zazie Beets and Bob De Niro have absolutely nothing to work with), both score and soundtrack are excellent, it's paced well and it has a suitably grimy aesthetic. It's technically proficient throughout, and it's certainly far more interesting than watching CGI minions get punched for two hours. But it is a morally dubious film, and due to its pretentions to be more than just a comic book movie, it cannot be written off as just a comic book movie. Saying 'it's not supposed to have a message' doesn't fly here. It has a message. It's just incredibly flawed, woefully misdirected and irresponsibly depicted.
To stretch the Scorsese comparison a little further, Goodfellas and Wolf of Wall Street initially glorify its characters' lifestyles and vices so it can drive them to excess and show the long hard journey to the bottom of the barrel; it seduces you with its pleasures before making you sick of the company you're keeping. Joker doesn't even attempt to do this; its first act desperately wants you to feel sympathy for Fleck, before depicting wanton acts of violence without the sophistication to frame them as negative in the context of the scene. Yes, a sensible person should look and say the things that Fleck does are bad. But when the film paints him in a Messianic, rock-star fashion come the end, there hasn't been enough time for the audience to grow sick of his actions the way we do Henry Hill's or Jordan Belfort's. We are supposed to revel in him dancing down the stairs to Gary Glitter (dubious in itself) after he murders innocents. We're supposed to laugh at his pratfalls in the final few frames. We're supposed to be in awe of Phoenix's confident stroll, mid-drag on a cigarette, as he literally walks in the opposite way to the police. The morals of this movie are all over the place. And that's what makes for the funniest joke of all.
That, in essence, Todd Phillips tried aping Scorsese in style, forgot to add the substance, and ended up doing what almost every single director who has taken a Marvel or DC comic property has done: made nothing more than a decent film.