Got to see it myself tonight, and enjoyed it a lot more than I thought I would; I’ve been through all of the novels twice, so I had some pretty well-developed notions of what the characters would be like, and I found things to cavil about in nearly all of them. Not nearly enough of the overgrown little boy about Crowe’s Jack Aubrey; granted that by halfway through the novels, Jack has matured and deepened a lot, but he’s still mostly “what you see is what you get”, and Crowe always seems to be more reserved than Jack. Bettany’s Maturin, on the other hand, seems almost callow, which is the one thing that Maturin isn’t. O’Brian establishes early on in the first book that Jack and Stephen are roughly the same age, but Stephen always seems somewhat older, wiser, and more self-aware. Bettany’s reactions to the other characters in the scenes of dinners in Jack’s cabins seemed off – not nearly detached enough, for one thing, and perhaps too willing to allow himself to join in the spirit of things. Billy Boyd was nowhere near physically imposing enough to be Barrett Bonden. James D’Arcy’s Pullings seemed perhaps a bit too slick, too sophisticated – it’s hard to see in him the character who, just a few years before this point hosts a big dinner in Gosport with his farmer father and extremely provincial mother and sweetheart upon being made lieutenant. I always imagined Preserved Killick as smaller and more wizened than David Threlfall, but he hit basically the right notes in his portrayal.
Generally though, the movie was faithful enough to the spirit of the books, and none of the complaints above really interered with my enjoyment of the movie as I was watching it. The battle scenes were confusing, but they should be.