This is that rare thing - a good comic-book movie. The Director [ Guillermo Del Toro ] like the source material, and kept the feel of it. The best comparison with this would be Sin City .
The title character is Ron Perlman, who previously worked with director Guillermo Del Toro in Blade II . Hellboy is a demon who was brought to Earth by Rasputin and an undead Nazi, members of the Thule Society. They wish to destroy the world and let Cthulhu take over, or whatever.
The infant Hellboy was rescued and raised by Professor John Hurt [ Alien ]. When he grows up he works in a team of superhumans, including Pyrokinetic Selma Blair and a fish-man [voiced by David Hyde-Pierce - Niles in Frasier, narrator of Mating Habits of the Earthbound Human ]. They're out to save the world from Demons and suchlike ...
It's a lot better than it sounds. The characters are well-rounded, the acting performances are real, the direction and SPFX are spot-on. The result is an entertaining self-knowing romp. Light-hearted without being camp. A real gem!