Vadim Jean's second adaptation of Terry Pratchett's longrunning Discworld series of comedic fantasy novels cannot compare to the first, though it is not really his fault. The series adapts Pratchtt's first two novels, The Colour of Magic and The Light Fantastic, which together form a loose single narrative. Set on a typical fantasy realm, replete with trolls, dwarfs and demons, they are, effectively, a parody of the hero's quest, in that the hero, an untalented "wizzard" named Rincewind, has no intention either of being heroic or of going on a quest but ends up fighting monsters, riding dragons and trying to save the world anyway. He is assisted by his "sidekick" Twoflower, who seems only dimply aware that he isn't on a packaged holiday. And that, without mentioning specifics, is the entire plot. Along the way, several fantasy (or perhaps D&D) conventions, such as talking swords, scantily-clad, Heavy Metal-style warrior women, and raging loin-clothed barbarians, are duly referenced and lambasted.
After the relative success of Hogfather in 2006, Vadim Jean decided to take the series in a surprising direction: backwards. Correctly in my view, he chose perhaps the archetypal novel in Pratchett's canon to adapt first. Hogfather was Pratchett at his absolute height, mixing adventure with philosophical commentary and existential humour, the most mature expression of such Discworldly themes of imagination vs. reality, the power of myth vs rationality, and the dichotomy of "the falling angel and the rising ape". "The Colour of Magic" and "The Light Fantastic" were written 25 years ago, when Pratchett was still finding his feet as a writer. As such, they lack some of the sophistication one comes to expect from the series. The books' humour, which would eventually become character and situation-driven, here operates on the level of broad parody, lampooning the absurdities of many fantasy and fairy tale conventions. The characterisation, which would become far more complex in later novels, is as broad as a wall, with Twofower the naive Asian tourist and Rincewind the cowardly non-hero. In a move that was either very wise or bewilderingly silly, Jean decided to cast Sean Astin as Twoflower, even though in the books he is East Asian in appearance. Perhaps this was done to lessen the racial stereotype, but if so, that doesn't reflect well on the source material. His decision to cast the elderly David Jason as Rincewind, who in the books is a youngish man with a scraggly attempt at a beard, is less explicable, other than Jean was simply grateful that Jason wanted to do another series with him.
But if the plot is slight, the actors certainly give it their all. Astin plays Twoflower with just the right kind of naivete, while Jason, though miscast, creates a Rincewind that is suitably cynical and craven. For Pratchett fans, a number of pleasing retcons have been incorporated: The Librarian becomes an orangutan much earlier; Death is now his fully-evolved, pleasantly bemused self, and the Patrician is unquestionably Vetinari, here played by Jeremy Irons- a nod to Pratchett saying that a good actor for Vetinari would be "that guy from Die Hard", ie Alan Rickman.
In summary, I think Pratchett fans will find pleasure in it, but others should probably stay away.