Hammer is good at sets, props, costumes, and casting overall. However, the writing for this one is on the weak side, as was the casting of Prowse as Frankenstein's monster and the makeup for the monster.
Frankenstein is played as a smart-alecky sociopath, which I didn't so much have a problem with. The people are him are rather stupid, which works out well for him but I found it a bit boring and perhaps it should have been played a little more for comedy than it already was. Prowse's monster is one of the least interesting monsters in any Frankenstein movie. He's a killer from the start, and then Frankenstein's attack dog essentially. He's also not merely large, but exceptionally fit, which just doesn't seem right.
Kate O'Mara shows off as much cleavage as is possible without showing more, suggesting Frankenstein perhaps invented tape. It didn't strike me as a particularly bloody film, so some of the other comments make me wonder if I didn't happen upon an edited version. I watched the Republic Pictures videotape released 1994.