Bowery at Midnight is not so much a horror film as it is a crime drama with a few small horror elements thrown in it. That being said, it's not a bad film. Bela Lugosi is good as Professor Frederick Brenner, a criminology professor who has a side hobby as the owner of a soup kitchen with nefarious intent. This role is a little different for him and while it's not his best performance, it is a role he is well suited to play. Director Wallace Fox also worked with Lugosi in The Corpse Vanishes which is the weaker of the two films. Fox is a competent filmmaker. However, Bowery at Midnight is nothing special in terms of either plot or cinematography. It's just O.K.
I was also lured into watching this film with the promise of zombies. Yes, zombies do appear in the film but are totally underutilized and not really central to the plot. They have very little screen time which was a big disappointment to me. You've been warned.
If you're a Lugosi Fan, this one is a must see because it is a solid effort. If you're not, but are still a fan of horror, then I suggest you first check out Lugosi in Dracula (1931) or Son of Frankenstein (1939). These two films are Lugosi at his best.
For more info check out the film's entry in IMDB.