This was a little confusing at first, and if you are a fan of the Sam Vimes books from the Discworld, you might make the confusion worse by trying to get your head around the characters and the plot bits. Best bet is to throw out all your expectations of the characters and take it from scratch lol. it is after all only 'inspired' by them.
That being said , once it gets going its really rather a fun watch and the music is brilliantly chosen, the stylisation of even the background characters is really gorgeous to look at especially if you like that punk rock image. Which i do!
So to sum it up, give it a go, have no expectations, and enjoy it for what is is, well worth hanging on past the initial confusion :)