I enjoyed the film. I have seen a lot of Tintin purists complaining that the motion capture technique doesn't give the same results as Hergé's ligne claire style. I think this misses the point; while it was OK to produce quickie animated films which were based closely on Hergé's style in the 1950s and 1970s, today's cinema audience won't take it, and animations are expected to look a bit more substantial. There is a very nice homage in that literally the first scene features Hergé himself as a pavement artist doing a sketch of Tintin's head (in fact I think he says the first spoken lines heard in the film). The 3D effects are duly spectacular, the action is fun and the humour remains.
The politics are somewhat dubious - it barely passes the first step of the Bechdel test, with Mrs Finch and Bianca Castafiore, who do not meet let alone talk about anything - but there at least it is faithful to the original. The two scenes that I found most memorable were Captain Haddock reliving his ancestor's encounter with the pirate Red Rackham, and Thomson and Thompson's confrontation with the kleptomaniac Aristides Silk, both of which are magnified and frankly improved from equivalent episodes in the original Secret of the Unicorn book (the twins/pickpocket scene definitely one of Moffatt's great moments). It's an entertaining film, though I think not a great one; and I'm prepared to allow Spielberg, Moffatt and Jackson the occasional bit of work that is merely good rather than excellent. Andy "Gollum" Serkis as Captain Haddock and Daniel "James Bond" Craig as the villainous Sakharine/Rackham particularly excel.
Reading the books last night and this morning, I realised to my surprised that the Unicorn/Rackham sequence was new to me; I had only read The Crab With The Golden Claws when younger. All three books are the product of Nazi occupation, when Hergé was trying to cheer up a brutalised populace with tales of derring-do in the supplement to Le Soir. The Crab With The Golden Claws is a farily straightforward tale of Tintin, not especially helped by the detectives Thomson and Thompson, investigating a mysterious death which turns to be linked to drug smuggling from Morocco. While the effects of the smuggled opium are not really described - it is assumed that the reader's parents will explain why it is a Bad Thing - there is much material about the effects of alcohol, incarnated in the new character of Captain Haddock. There's also an possibly sinister Asian character who turns out to be a Japanese detective and therefore a good guy. The moral, if there is one, is that things are not always as they seem, and depths are usually hidden.
Crab's contributions to the film include the story of how Tintin and Captain Haddock actually meet, and the sea voyage and landing for an exciting time in a Moroccan port. I noted several changes from these elements as they were adapted for the screen. First off, Haddock's destructive alcoholism, which teeters on the edge of being really not funny in the film, has actually been toned down from the book where he repeatedly and deliberately endangers himself and others for the sake of his addiction. I think the film makers moved this in the right direction, though not necessarily far enough. Once we reach Morocco, Omar Ben Salaad has been transformed from scheming Arab merchant and drug smuggler to genial local potentate with a taste for model ships and opera singers, who then gets his palace and town smashed up by Tintin and his enemies; and finally - think I caught this right - the seaplane which attacks Tintin, Haddock and Snowy is mysteriously said to have Portuguese markings in the film rather than Moroccan as in the book (which would make more sense). While the upgrading of Ben Salaad's character to victim rather than villain is probably an improvement, he still has an offensively silly name and the commander of the desert army fort is still mysteriously white.
Most of the film is, not surprisingly, taken from The Secret of the Unicorn. The original book is one of two Tintin adventures set entirely in his home country, chasing around the back streets of the capital city (and the mansion of Marlinspike) to try and track down the three parchments which put together will reveal the secret location of the treasure lost by Captain Haddock's ancestor. It has a lot of fun and action, and one very effective info-dump sequence where Haddock retells the events on the Unicorn in the seventeenth century (though as noted above I think the film does this even better). There is a less successful infodump near the end when one of the villainous Bird brothers explains what has really been going on. The antique dealer Sakharine, who is the chief bad guy of the film, is here a largely innocent bystander who vanishes without explanation. There are also some breathtaking moments of artwork, but actually the structure and plot are not without flaws.
Though I had not read Red Rackham's Treasure, I had at least seen the 1959 Belvision animation and remembered the incidents of the wrong longitude (which is not in the film) and the statue of St John (which is). Though in fact the actual finding of the treasure is almost the only part of the book which made it to the screen this time, most of the rest apparently being saved for the next film which will also combine parts of The Seven Crystal Balls and Prisoners of the Sun. This means no trace of the book's main new character, Professor Calculus, whose shark-shaped submarine is vital to the expedition to retrieve the treasure, and whose unconsciousness of his own deafness makes him one of the most fascinating characters in the whole Tintin œuvre; he appears to operate in a blithe parallel reality which only occasionally intersects with ours. Again there is some goreous art, particularly the moment when Tintin finds the wreck of the Unicorn on the ocean floor. Apart from that, the moral of the book is that grand expeditions and expenditures may not always deliver the same results that you might have got from looking closer to home. I liked it the most of the three.
Anyway, @quarsan asked me for a summary review, which is that the film is good but not great, and the books are well worth reading but there is better to come.