Tim Brayton’s review published on Letterboxd:
In retrospect, of course Warner Bros. wasn't going to put out a movie that genuinely grappled with Fred Hampton's revolutionary politics, and it's on me that I was idiot enough to wonder if they might. Instead, despite a couple quotes from Marxist literature, and one appearance each by the words "socialism" (at the start) and "proletariat" (at the end; also, I might have missed a "proletariat" in there, I wasn't really thinking to count it), this mostly turns Hampton into a generic "the bad things are very bad" rhetorician, who talks a lot about revolution and gets very keyed up about it, but never gets around to pinpointing what the revolution will consist of or what it will lead to. You can't tell Hampton's story and leave socialism entirely out of it, but you can try, and this movie does a pretty good job of reducing him to a cardboard icon, with all the revolutionary potential of a Che Guevara T-shirt.
I am, of course, being a least a little crabby about a movie that will, beyond a shadow of a doubt, bring Hampton to far more people's attention, and if even one-hundredth of these people actually read up on the man and not the scrubbed version of him the film presents, then we're getting somewhere. Also, it's at least a perfectly adequate movie; a little overindulgently lit and hopelessly light on narrative thrust (almost all of the dramatic conflict is about Bill O'Neal's increasingly nervous collaboration with his FBI handler), but the production design and costuming are very good, and the performances are just about everything one hopes they'd be. Daniel Kaluuya is great, despite being catastrophically miscast (it matters so much that Hampton was just 20 and 21 when he achieved all of this, and Kaluuya is not a young-looking 31), spitting fire and nailing all of the vocal modulations of an inspiring rhetorical Wunderkind; LaKeith Stanfield is even better, capturing this film's perhaps generous portrait of O'Neal as a scared, conflicted, self-loathing traitor in all its complexity. Jesse Plemons very wisely realises it's not his film and just says the lines.
All in all, it is what it is: an Oscarbait biopic. An appropriately dangerous movie on these themes wouldn't be within sniffing distance of any major awards, and it wouldn't have premiered at Sundance, one of the most cozily bourgeois film festivals out there. But it's not by any stretch the worst Oscarbait in contention right now. Anyways, if you liked this, you'll love The Murder of Fred Hampton.