Bowery at Midnight was one of many cookie-cutter horrors starring Bela Lugosi at the beginning of the end of his career (halfway between Dracula and Glen or Glenda). I'm not sure how I feel about Lugosi. There is no denying that he has a certain screen presence, but it's the same presence that he dusts off and uses in role after role. Whether this is because he was limited in his range as an actor or because he was rigidly typecast is hard to say.
Having said that, I did somewhat enjoy his performance in this movie. He plays a psychology professor who runs a soup kitchen by night under a different name. He uses the soup kitchen as a means to recruit criminals into his robbery schemes, and then he disposes of the criminals when he is done with them.
This was really more of a psychological crime story than a zombie movie, but the zombies were indeed there. Lugosi has a doctor sidekick, who, unbeknownst to Lugosi, is taking the bodies of the criminals and reanimating them, keeping them hidden beneath a false grave in the basement. However, the zombies are almost an afterthought. I have the feeling that the producers had a crime story script and Lugosi, and decided to throw in some zombies, since they thought nobody would watch a Lugosi movie unless it was a horror.
One interesting thing about this movie is that it may be the first instance of flesh-eating zombies on film. They don't actually show anyone being eaten, but there is a point where the doctor throws a corpse down to the zombies, telling them to enjoy the meal. (There are some details to this plot point that are unclear, but I won't go into specifics. Let me just say that at the end of the movie, I was wrinkling my brow in confusion.)
This film is historically interesting, but not particularly gripping; I would recommend it if you're a Lugosi fan, but otherwise you will probably derive only modest enjoyment from it.