With some film series, you can tell at a certain point where it is only being continued for the money. The good news is that this film isn't that point. The bad news is that that point was reached all the way back when Hannibal was released. Quick recap of the series:
Silence of the Lambs - The epitome of what a thriller should be. Hopkins and Foster were both fantastic, the script was brilliant and the directing was marvellous (5 stars)
Hannibal - Helmed by the still capable Ridley Scott rather than Jonathan Demme. This was the cash-in film of the cash-in book. A wonderful character becomes less like his original incarnation and more like Sideshow Bob. A decent plot, but it just doesn't fit next to the original. (2 stars)
Red Dragon - A welcome return to form. The attempt to make Hopkins look younger are rather transparent, but a good cast and a engaging storyline made this a welcome part of the series. (4 stars)
(Also Manhunter, but I haven't seen it)
The most obvious problem with Hannibal Rising is that

is no

French star Gaspard Ulliel may be talented in his own right, but he just doesn't feel like the character that Hopkins made his own.
The second major criticism is that another prequel was highly unnecessary. Red Dragon explained how Lecter was captured, which was quite a nice touch. But knowing everything about a character doesn't always make them any more three dimensional, and if anything , often takes away some of the mystery. The Empire Strikes Back was a fine film before the full history of Darth Vader was given. The same applies here.
The contradiction is that this doesn't really feel like the childhood of Hannibal Lecter. Without giving any secrets away, this is a story of Lecter seeking vengeance against those who wronged him. There is no causal connection between the revenge seeking killer of Rising and the psychotic Hannibal Lecter who killed a flautist for being untalented. The most worrying thing about this is that it implies that there could be yet another sequel still to come.
Much of the subtlety of Silence and Red Dragon is gone as well. Whereas in Silence, there was a subtle inclination that whilst Hannibal was a monster, he still had more redeeming value than glory-seeking hypocrites like the warder, Dr Chilton; in Rising, you are clearly meant to be rooting for this cold-blooded murderer.
My biggest problem with the film was that, if 3 minutes or so (the cannibalism related footage from the part of Lecter) was selectively cut from this film, the only connection with the series it would have is the character's name. By connection with Silence of the Lambs, this film is inherently compared with one of the best films ever made, and suffers for it. As part of the series, I'd give this about 2.5 stars. But taken on its own, this film has the emotion and intensity that Kill Bill wishes it had. The hatred shown on screen is almost palpable. If you can overlook the identity the protagonist, then this film is at least a 4 starer.
(Plus, Rhys Ifans as a villain has to be worth almost a star in itself)