The personalities of Hellboy himself, and that of his perpetually sleepy-looking girlfriend Liz Sherman, are wonderful to revisit. Neither are particularly known for their optimism, and their dour interplay is relatable to the real world in a way that is quite nice to see. For that reason alone, Hellboy 2 is worth seeing.
But Hellboy 2 suffers from the same problem that many comic book movies suffer from: the need to have a big show-down at the end, usually on an elaborate soundstage set. Tomb Raider had its wind-up solar system, for example. Same thing here. At this point it is such an unoriginal way to end a a comic book movie I wonder why anyone does it anymore.
But at least for 3/4th of the film you get to enjoy the interplay of the characters a bit.
I think what the world needs is a superhero film that ends on a more arty note, like, they just punch their time cards and go to bed.