I'm a fan of late 50s/early 60s B&W horror and monster movies, and this is one of my favorites. Yes, it has all the cliches of the low-budget, slapped together flicks of this genre and time period, such as alternating daylight and darkness within the same sequence, poorly-written script ("I know it's impossible, but It's the only possible explanation!"), and cheesy special effects. It's also has a climax that pushes the movie beyond cliche: it takes place on top of a dam in mountain wilderness, with water cascading thunderously like Niagara Falls. A dam that had not been seen or heard in any of the previous scenes that occurred just a few yards away. Which conveniently empties into a bottomless pool. It's impossible, but it's the only way possible.
Review of Giant from the Unknown
