I usually don't bother to write reviews if I don't think I can add anything to what's already been said, but since most of the people who've written reviews seem to be B-movie aficionados/enthusiasts, this is a review for the rest of us non-film-buffs.
I thought it wasn't half bad really. Obviously supposed to be a psychological thriller, and most of it holds up surprisingly well to today's standards. Of course the characters are pretty stock standard, but Chet's story and his psychological progress throughout the movie were interesting.
The main reason I give it only three stars would be a spoiler, so I'll leave it out, but I will say that Chet's girlfriend made me want to change the channel, even taking into account that this was made in 1961. Ick.