I can't say anything other than the fact that I'm highly disappointed. Karloff(usually pretty good) and Lugosi(could be good) were never great actors and are basically good at just one thing, looking scary(exaggeration). It will therefor be a bad idea to put them in a film that requires them to have long dialogs and show emotions. Their supporting cast is also incredibly weak, at best they "try" to be theatrical. Were did they find these people?
Luckily for them they can give the excuse that the plot and dialog was rubbish as well. There's no real room for character development and it rushes over everything. All thought of these peoples mental states are overlooked. Lugosis character wants to kill Karloffs but waits and waits and waits even longer. The reason he gives at first is that he doesn't want married couple put in danger but even when they are he just plays along. As a matter of fact circomstances is the only reason why the wife isn't killed.
At numerous points in this film I can't help but ask myself whether they were running out of film. Not only is it just an hour long but they rushes everything and just jumps from setting to setting. Also the movie never takes the time to show details "The car crashes, guy takes one look and says "the drivers dead", all of them wanders up without saying or discussing anything".
And why doesn't he kill Karloff whenever he gets the chance? Because then the suspense would be over. Oh and lets mix in a satanic cult - and then forget about them completely. Oh and the brief comedic duo, give me a break, mildly amusing but hardly worth anything. This is so thin one could cry. And again back to the acting: look at how Bela reacts to the cat or how is servant looks when he first falls. And just look at the actors faces, expressions, etc. Karloffs servant for example.
The direction was incredibly mediocre as well and there's not too much atmosphere. He does try to play with shadows a little bit but he's not too successful. He is also the one who could be blamed be blamed for the rushing. It's like he doesn't want us to get to know anyone. This is clearly not a character drama(no need for it to be), but we should get something.
And why in the world call it the Black Cat? This is based on Poes poem? Bela sees a black cat in two scenes and it has a connection to satanism?
It's pretty clear to me that this was thrown together extremely quick and was made only to make a few fast bucks.