For most screenwriters, the time-gap between completing a script and having it judged by your audience can be sizable. Not so Quentin Tarantino, who completed his screenplay for upcoming movie Django Unchained on 26 April and earlier this week woke to discover half the blogosphere had already read it. Many sites reprinted the front page, loving completed in QT's own childlike scribble, to prove they had seen the script. Did somebody at the all-day party Tarantino apparently held last week to celebrate its completion nip off and make copies? Or did someone at the Weinstein Company decide to slip a few in the post to key players? No matter: the word on Django Unchained is out there, and it's too late to shoo it back into its box now.

Tarantino has refused to confirm any of the speculation regarding the film, so the below should all be taken with a fairly large dose of salt. Nevertheless, here is what we think we know (thanks mainly to Matt Holmes at Obsessed With Film, who has posted an extensive script review). First, Django Unchained seems to be an homage to Sergio Leone set in the deep south (rather than the old west) which tackles the predictably difficult subject of 19th-century American slavery. The lead character is a black slave-turned-gunslinger named Django.

Second, the film appears to feature a plum role for Christoph Waltz, the Austrian actor whose performance as a dastardly SS colonel in Inglourious Basterds was rewarded with an Oscar last year. The part is that of a German bounty hunter and former dentist named Dr King Schlutz, who teaches Django the art of contract killing before helping him to find his still-enslaved wife. "The part has clearly been written exclusively for Waltz in mind," says Holmes.

Waltz hasn't yet been officially confirmed in the role, but Anne Thompson reports that Tarantino's agency, WME, believes the actor has already been cast. Anyone else get the impression that, in the wake of Basterds, every Tarantino script from here on in is going to feature a conspicuously Teutonic character? Given that he already has to shoehorn Samuel L Jackson into everything he does that doesn't leave the director a whole lot of room for manoeuvre, but at this stage it's hard to blame him: what screenwriter wouldn't be salivating at the prospect of dreaming up dialogue for the actor who delivered his last film's tour-de-force opening?

What of the title? Well, Tarantino seems to be repeating the same trick he pulled with Inglourious Basterds, which borrowed its moniker from a 1978 Italian war film of (nearly) the same name but ignored pretty much everything else. The original Django is a 1966 spaghetti western, directed by Sergio Corbucci and starring Franco Nero as a ruthless gunman. Nero said he's been given a role in the film, but that may well be the only connection – other than that Tarantino will riff off the genre's tropes in much the same way he cheerfully rifled through the "dogs of war" domain last time around.

Ain't It Cool's Harry Knowles tweeted on 3 May: "DJANGO UNCHAINED is an operatic southern… this is my favorite QT script. & I've read them all. This I absolutely love at every level." Not everyone has had the same reaction. Holmes reports that the 166-page screenplay is overlong, self-indulgent and defiantly non-commercial. "There is nothing for Joe Popcorn to cling on to here," he writes. "This isn't a movie that young teenagers/adults, unless they are huge fans of Tarantino, will get off their ass[es] to see in their droves. Tarantino is playing for a niche market here – nobody has really made a movie about race like this for years, and when they did it was never for a mass audience."

It may well be that the Weinsteins are faced with reining in a film-maker whose confidence must be sky-high after the critical and commercial success of Inglourious Basterds – though that in itself is a dangerous game to play. Often, it's when Tarantino appears to be at his most self-indulgent that the magic happens. What producer in his or her right mind would have allowed the director to split Kill Bill into two movies, the second of which is hugely dialogue-heavy and features very little action? And who apart from Tarantino could have got away with turning a bizarre Jewish revenge fantasy about the Nazis into the weirdly workable movie that is Basterds?

Reining in Quentin Tarantino would be like telling Jimi Hendrix to quit with the guitar solos – and yet someone might have to do it. Could that be the secret behind the screenplay's bizarre leaking? After all, if you're determined to win an argument, there's nothing like having a bit of backup.