We've been hearing about Quentin Tarantino making a cowboy movie since roughly the same time that D:Ream were at the top of the charts; Django Unchained is arguably the most anticipated film of his career to date. What's in no doubt is that it's the most controversial, as Tarantino applies his trademark mix of humour and horror to a 'Southern' (not a Western, mind) about slavery and revenge back in 1858.

Leg-ironing his way towards an even more wretched future, slave Django (Foxx) is freed by Dr King Schultz (Waltz), a German dentist-turned-bounty-hunter who has a business proposition. While Schultz is a liberator, he's also an opportunist: he needs Django's help to track down some vermin who are on his hitlist. Django takes up his offer; the long trails forge a friendship and soon he and Schultz have become the scourge of fugitives across the South.

But now it's the turn of Schultz to answer Django's call - he needs help in rescuing his wife, Broomhilda (Washington). She is among the slaves down on Candie Land, a plantation owned by the demonic-looking Calvin Candie (DiCaprio) and run day-to-day by his house servant Stephen (Jackson). And so Schultz comes up with a good plan to get Django's wife back; the question is can he keep his emotions in check long enough for it to work, or will the three of them end up six feet under in a Candie Land field?

Bloody from the get-go and with moments of brilliance scattered throughout, Django Unchained is less pretentious and far more powerful than Tarantino's Inglourious Basterds but also shows that middle age isn't mellowing the genre-masher one bit. From appearances by Little Joe's green jacket from Bonanza, The Warriors' James Remar as Calvin Candie's enforcer, special effects genius Tom Savini, Bruce Dern, one-time Duke of Hazzard Tom Wopat and Matt Houston star Lee Horsley, it's a cult movie and TV fan's dream, but Tarantino also manages to work in stark reminders of the realities of slavery. While it does feel as if the audience is being invited to play racial epithet bingo, this is still a movie to get you thinking. And squirming.

It's also a movie that could have been a half-an-hour shorter, as once again Tarantino has overdone it with the verbals - James Brown's The Payback features on the soundtrack but Talkin' Loud and Sayin' Nothing would've been a far better choice. In Django Unedited, momentum is lost many a time because of a fascination with guff and if a three-and-a-half hour Ultimate Cut ever emerges, it will be one of those times where you can say with complete certainty that life is indeed too short. A backside can only take so much numbing.

In the here and now however, and despite those faults, one thing above all else makes Django Unchained worth seeing for both Tarantino devotees and detesters alike: the strength of the performances. Foxx hasn't been this good since Ray, bringing the menace he exuded in that scene with Javier Bardem in Collateral across this entire movie. Waltz is genius once again as the invariably chipper bounty hunter who's as impressive with his turn of phrase as a six-gun. DiCaprio revels in sending up our image of him as a screen hero - he really should do more comedy.

And then there's Samuel L Jackson.

Despite the fact that Tarantino, Waltz, cinematographer Robert Richardson and the producers have been nominated for Oscars, the one person who's shamefully missing from the list is him. Bringing to life one of cinema's greatest grotesques here as Stephen, Jackson's failure to get a nod as Best Supporting Actor is the most glaring acting omission since Paul Giamatti for Sideways. Switching from banter with DiCaprio to menace with Washington, this could indeed turn out to be the best performance of Jackson's career. You'll certainly be remembering Stephen for the rest of it.

Saddle up, but do bring a cushion.

Harry Guerin