Frankenstein in use as a kaiju has always been a weird one. Sure, I suppose it makes sense, he's a big freak made in a lab. Go figure some radiation could make him giant. He made one hell of an awesome villain in Power Rangers (that was an ass kicking he dealt out). It's just his portrayal comes off more bizarre than anything. Which once again, bizarre works for Frankenstein, but once he becomes a giant, he just kind of looks like a caveman. I suppose wearing fur didn't help with that, but it is what it is. Can't have him grow gigantic and somehow his pants still fit. Good thing the Gargantuas are furry monsters to avoid that awkward issue. Man, Frankenstein's weird yelling just doesn't help. I think Frankenstein in Power Rangers/Super Sentai was better, even though his pants grew.
Boy, a living severed hand is always a great monster on it's own though, isn't it? The least realistic it looks, the better.