How to describe Baccano!? It's like a cross between Pulp Fiction and Benny Hill. Over-the-top blood and gore with an undercurrent of sheer absurdity, and a soundtrack rivaling that of Cowboy Bebop, make this a must-watch for any anime fan, or anyone who appreciates novel storytelling.
You really need to watch it twice: once to learn who everyone is and what's going on, and once to mentally fit together the pieces of the anachronic puzzle. Baccano! weaves together the diverse threads of several different storylines, cuts the cloth into confetti, and throws it over the viewer in a joyful celebration with no-nonsense episode titles like, "Ladd Russo enjoys talking a lot and slaughtering a lot," and, "Czeslaw Meyer is forced to rework his tremble-before-the-specter-of-immortals strategy."
Mostly set in Prohibition-era U.S. (with a some scenes nearly two hundred years earlier and almost a hundred years later), the story is driven by a few different crime families, a reporter, assorted thugs and gang members, a couple of incredibly ineffectual criminals, some cultists, and a group of alchemists seeking to recreate the elixir of immortality last seen in 1711.
Almost uniformly horrible people, the characters are oddly endearing. Vino's zest for life and penchant for being covered in the blood of his victims, Ladd Russo's bizarrely romantic declaration of murdering his financée last of all, petty thug and bully Dallas Genoard's affection for his little sister: these are all people you have a twisted affection for by the end of things. Combined with Isaac and Miria, the two most loveably inept thieves you could ever meet, the tone of the whole is downright heartwarming. Blood-spattered, but heartwarming.
If you haven't gotten the hint, yet, this show must be seen to be believed. Go see it for yourself.