GANTZ should probably be on the "pretty gory" list. The main characters get hit by a train/decapitated in the first episode, and it goes on from there. Lots and lots of gruesome deaths.
And Baccano!'s pretty gory in parts, but it's not the main theme. One guy has his face pressed onto train tracks on board a speeding train so it all grates away, and another kid gets hot pokers in his eyes, and a few people are strangled till their eyes burst I think!