“Same rules apply.”

James McAvoy gets to say this a few times as Bruce Robertson in the movie Filth. The adaptation of Irvine Welsh’s book of the same name is directed by the relatively unknown Jon S. Baird, and it’s pretty great. The plot revolves around Bruce, a manipulative bastard of a cop, trying to win a promotion. He does this by generally being comedically Machiavellian and monstrous. It becomes clear very early on that Bruce is not well; there’s something much darker coiled around beneath his veneer. As the movie goes on, Bruce’s plans and sanity increasingly fracture and begin to escape his control.

It’s a smart movie. Baird realizes that Bruce’s behavior, even the funny parts, or particularly cruel parts, could seem a wee bit too compelling. Every time this starts to become a risk, he gives the audience a little taste of Bruce’s truly tenuous command over his appearance. Sometimes it’s as simple as a faintly broken look passing across McAvoy’s face after a certain line of questioning, and sometimes it’s a truly shocking visual hallucination – actors’ faces replaced with animal masks, a dying boy, and a terrifying imagined therapist all appear in fairly cutting moments. The further into the movie you get the more regularly this happens and the more manic Bruce gets. He ends up spending a large portion of the movie laughing and crying and afraid, caught in his twisted mass of emotions. As this goes on, the film peels back the layers of Bruce’s mania, eventually revealing the events that are responsible for (some) of his disturbing neuroses. It’s all fairly well executed, managing to never feel exposition heavy or clumsy.

It’s a clever movie in other ways too. It’s pretty plainly a character study, sure there’s plot to it, and a lot of it is important, but the movie is really about Bruce Robertson. He dominates every scene, and the film does some interesting stylistic things in order to mirror his mindset. The first two thirds of the film are fairly glossy and slick. Clean colours, camera movements, and editing. The music kicks in a little too loud, feeling a little false. Hell there’s even an impromptu kind-of-musical number. This veneer only cracks the first few times he starts to have visual hallucinations; the film’s language starts to feel more like a horror movie in these moments, complete with jittery editing and off-balance shots. Filth feels sicker as it progresses. Warped wide-angle lenses and significantly grimier shots provide an effective mirror for Bruce’s mental collapse.

The movie belongs to James McAvoy though. He dominates the vast majority of the film in the most literal way. There are barely any shots without him, and he tends to command the majority of the frame every time the camera is pointed at him. His performance is brilliant. He’s like a machine, hitting every mark with alarmingly brilliant accuracy. The movie essentially oozes McAvoy, and it’s perfect. Every time his character gets away with an especially clever piece of manipulation, McAvoy’s eyes just slither over to look at the camera. It’s pretty reminiscent of what Kevin Spacey does in House of Cards, except that Filth doesn’t fully follow through on this fourth-wall break until the last moments of the film. In good faith, I couldn’t possible reveal the nature of the ending, but suffice it to say it is absolutely wonderful, one of those rare endings that’s pretty much perfect. McAvoy doesn’t just excel at playing Bruce Robertson at his most manipulative, his subtle glimpses of weakness are powerful and poignant, and that’s barely scratching the surface of what he does. Bruce Robertson’s eventual savage crash and burn, which is all fire and mania and crippling depression, is unbelievably effective. Without McAvoy’s performance the film wouldn’t be half as good. Even that brilliant ending I alluded to before only works because of McAvoy – he’s unquestionably the heart of this film, and it’s a loudly beating heart at that.

The rest of the cast is good too. Jamie Bell is good as the police department’s resident rookie – a rookie with a cocaine addiction and a serious inferiority complex (his minuscule penis is a plot point at leas twice) no less. Jim Broadbent gets to be Jim Broadbent in what essentially amounts to an extended cameo appearance. Eddie Marsan probably has the second biggest role after McAvoy, and he’s very convincing as the wealthy, shy comrade to Bruce Robertson. The resident female characters are good too. They don’t have a ton of screen time but both Imogen Poots and Shauna McDonald have fairly important roles, and they both execute them flawlessly.

Speaking of flawless, the film comes complete with one of the better soundtracks in recent memory – at least when it comes to soundtracks consisting of preexisting songs, a personal fascination of mine. It includes a healthy dose of Christmas music (did I mention this twisted film largely takes place over the holidays?) and an unplugged version of Radiohead’s Creep. Creep especially is amazingly timed, matching the tone of the last scene bloody perfectly.

If it seems like I’m throwing a lot of praise around that’s because I am. It’s a really great movie, but I’m not entirely convinced it’s the work of a great director. Jon S. Baird definitely fancies himself one (you’ve got to think so to make such a blatant Kubrick reference) but it’s hard to tell how much of what makes Filth work is from approaching the source material smartly. Sure there’s some clever camerawork and a great soundtrack but the backbone of the film is the plot and dialogue (clearly the best bits are straight from the book) and James McAvoy’s performance. It could be that Baird was brilliant in his own right, and understood how well sticking to these guns as cleanly as possible would work. However, it also seems possible he was a little lucky. Filth is a wicked movie, and hopefully it will continue to garner a reputation, but Baird remains a bit of a mystery. Rest assured though I’ll be watching his future career with anticipation.

Oh and James McAvoy should probably win something for this film. Seriously, his performance is that good. He makes the film completely hypnotic. He refuses to release your attention. Moments from that film are absolutely burned into my memory. Bruce’s hallucinations, various shots of McAvoy, and that fucking ending (seriously, if any of you watch the film hit me up on Twitter so we can talk about the last moment of that film (and by talk I mean trade excited blasphemies until we calm down)) keep playing through my mind. Whenever a movie sinks this deeply into my psyche it’s wonderfully exciting. This is why I hope Jon S. Baird’s next movie is just as excellent.

I’m going to leave this quote here so I can imagine James McAvoy Scottishly whispering it:

The games are always, repeat, always, being played but nobody plays the games like me, Detective Sergeant Bruce Robertson, soon to be Detective Inspector Bruce Robertson. You just have to be the best, and I usually am. Same rules apply.