Sadly, not quite what it could have been.
Personally I enjoyed it. As a matter of fact, I still play it every once in a while. But I can't help mentioning some details that it could have improved on.
Graphics: They're good. But not great, well not at least what could have been. I won't prolong this too much as I think they're just decent. I would have preferred a bit more detail on Wolverine at the very least, as well as the rest of the cast. When I saw the initial cinematic I was thrilled at the thought of a game that would deliver graphics like Tekken: Dark Resurrection. (The cinematics look quite similar in a way). But it was quite disappointing to find out that only the in game movies would sustain such quality.
Movement: Very fluid in my opinion. Especially Wolverine's. Very reminiscent to God of War: Chains of Olympus though. But if they had decided to copy that, they could have gone all the way with it.
The gore. People, the gore! How could they miss that? For the "T" rating?! I assure you with an "M" rating you would have gotten about the same revenues (perhaps even more considering the comic book fans out there with a PSP.) It's a Wolverine game! It's quite lamentable to see our clawed superhero with a foul temper neutered in such a way that he's limited to slashing out a few blood spurts from the enemies.
I would have LOVED Wolverine charging on bad guys like King Leonidas did on 300:March to Glory! The blood, the flying limbs, the decapitations. It was bewitching!
The enemies, quite generic. With it's standard level of difficulty. Forgettable. The gameplay is quite repetitive, just hack and slash your way in and out of the levels.
Bonus/Unlockables: Not a big deal. Except the 3 unlockable costumes: X-Men the animated series costume, Classic Wolverine and X-Force.
The bonus challenges can get quite tedious. Especially with a camera that sometimes refuses to help you out, determined to make it impossible to view enemies that are lunging towards you when you're trying to avoid them at all costs in order to succeed in the challenge.
Overall I find it an enjoyable game. If you're a Wolverine fan it's a must. But not easily recommended for someone looking for a great beat-em up.