Straight up, this is a mish mash of genres: crime, comedy, drama, suspense, action and probably a few more. Something for nearly everybody and all those ingredients in the end form a decadent cake that may be brief but tastes delicious. The ambient jazz goes perfectly for your meal, but more on that later.
It takes place in the 1930's and this is probably the first anime I've seen set in that period. I don't know much about the '30s so I don't know if alchemy or immortals were commonplace back then. But you can bet that makes it more fun; even if it was just mafia and Issac and Maria, it would still be great.
The story zigzags, going from one year into another, another year back, forward again and then way back only to come back to the '30s. It's strange, and it makes the viewer remember the events that occur previously as one part could be seen through one set of characters and then another perspective through another set or how one segment can interlock with another and add another piece to the puzzle. As strange as it was, I enjoyed it. It was different and even though it took a bit to get used to, it grew on me. It wasn't a straight line, but one that twists and curves to it's own beat.
But as much as I enjoyed the story and it's style, the writing exceeds it; in particular the characters that fuel it. And yet again, in particular, the duo Issac and Maria. Absolutely the best this show has to offer, and even though there are quite a number of excellent characters, these two are the best. And even though they are morons, I love them for being such. From their wacky costumes, mannerisms and personalities, funny dialogue and just about everything about them. They're just so likeable. The other characters are great, especially the psychotic Ladd; who isn't just that, but an amusing, crazy, joyful psychopath. I could go on for a few more characters, but that would spoil everything. Simply put, the characters make it more fun than it already is.
And as a side-note; as funny as it is, it has it's moments of darkness and moments of sheer violence that can surprise the viewer. No spoilers, but it's violent at times. Quite bloody. Just wanted to get that out of the way.
It certainly isn't dated and it looks good. Not much to say, apart from how good everything looks. Definitely love the realistic looks to the characters.
From the magnificent up-beat, fast-paced OP to the slower, more somber EP and everything inbetween, the music is a feast for the senses. The jazz is perfect feels like it belongs there and suits it better than any other form of music. And it would be ruined if the voices weren't as good, but fortunately they're superb. And by supurb, I'm refering to the english dub, as no other sub or dub could compare to it's majesty. I mean, the accents, the lunacy in Russo's voice, how Issac and Maria's voices work in perfect harmony with their characters... this wouldn't be nearly as much fun if the voices were off; the voices and characters work in perfect harmony.
What I remember most from Baccano! is how fun it was, how fast it went and how it zipped and zoomed while slowing down at times while keeping the viewer glued to the screen. The cast is great, the music is great, the VO is simply amazing and it's just simply packed with the stuff that makes anime great. It's just... fun.