Jeff Light’s review published on Letterboxd:
This isn't really an egregiously BAD movie, it's worse... it's just really dull. I watched the MST3K version, and it should've been a slam dunk, but not even their jokes could raise much more from me than a few chuckles.
Okay, okay, my bad for watching this at the end of the night after being out and having had a few beers. Okay, many beers. I figured that would've been the perfect state to appreciate the hammy old British acting and desperate attempts at early '60s special effects. But no, it was just desperately boring and hard to get into. I found myself repeatedly struggling to stay awake, much less interested.
Just to be sure, I went back the next day and skimmed through...yep, ponderous. I mean, there are a few attempts by the actors to dig in and chew some scenery...everyone seems to know what sort of movie they're in. But some of the actors have the ability to sell that and make it enjoyable. Many don't. And the director doesn't seem to know who can and who can't. The result is a really mixed bag where the tone isn't managed. It's not quite the wonderful misfire that would make for a great MST3K mockery, and it's not quite the enjoyable cheese that later efforts like Clash of the Titans (the '80s one!) would be.
In the end, this is neither Harryhausen nor Harry & The Hendersons... it's just zzzzzzzzzzzzzzz...