This is airing on Svengoolie tonight, and I haven't seen it in years, so I'll be giving it a viewing. It's fun to watch these old movies, since Channel 2 loved them some Universal monsters back in the day. They aired most of them multiple times, which made me love them growing up.
I think this was the first "monster vs monster" movie ever made which later paved the way for movies with even more monsters in them. For kids that loved seeing monsters on their big and small screens these were fun movies. They were never quite as scary when interrupted by commercials, either.