It's the last and worst of the three Creature from the Black Lagoon films. That's only my opinion, of course. I wouldn't argue with anyone who preferred it to number two, partly because of the superior character work and partly because it doesn't fall apart towards the end. It has good points. Unfortunately it's unscientific gibberish even by the standards of a 1950s monster movie, harsh though it is to judge this famously hare-brained genre on such criteria.
What I'd liked about Revenge of the Creature was that I could get behind what its scientists were doing. It held together despite the odd blooper, it made for a strong theme and it was a sufficiently worthy goal that for its sake I was happy to watch half an hour of the Creature being studied in a fish tank. This second sequel though is doing the opposite. These new scientists' motivations are so half-baked that there's nothing for me to get behind in the first place. I'm not merely calling it scientifically flawed. That I could have lived with. On the contrary, this film's technobabble isn't coherent enough to sustain flaws in the first place, instead being a mush of silly sentiments that think they're profound. Maybe I'm being pompous and nitpicky here given that this is a 1950s monster movie, but I still think it matters because we're talking here about the protagonists' motivations.
Righty-ho. Time for a 1950s science lesson.
1. If you capture a gigantic prehistoric man-monster, it only takes a few days to trigger profound changes in its physiology and mental processes. We're talking about evolution-level changes, but within one individual instead of entire generations. In fairness there was a 19th-century biologist called Jean Baptiste Lamarck with similar ideas, but he lost out to Darwin. Anyway, this element of the film (i.e. the entire plot) was always going to look silly and under-explained, but a further problem for audiences today is that we can do what they're talking about! We can make these kinds of changes in living organisms. It's called genetic engineering and it bears not the slightest resemblance to what we see in this film. In fairness there's an explanation of how the Creature goes from being a water-breather to an air-breather, but frankly the film would have been more coherent if they'd explained it all by having Tinkerbell turn up and sprinkle pixie dust.
2. "Nature hasn't created a new, major type of animal on this Earth for over 400 million years." That's nearly twice as far back as the earliest dinosaurs and indeed before the time of the first land vertebrates.
3. Triggering evolution-level changes in a single individual is what will get mankind into space. This is the 1950s, you see. They thought Mars and Venus would be inhabitable if you didn't wear a jumper or put on sun cream or something.
Anyway, the plot doesn't work. It's about scientists trying to do something absurd, which then miraculously happens by itself. Furthermore the lead scientist is a paranoid nutcase and the others tell him he's all wrong in his ideas, but this is just a token objection for info-dump purposes and they then go along with his ideas and never raise a squeak against him.
You've also got mundane goofs, the kind of things I overlooked in the last film and aren't really a problem here either, but are still there. "He led us into this river!" Uh, no, wasn't it him following you? I was openly laughing at their safety procedures with the bandaged Creature, who's just lying there with no restraints because he's snapped them. Then there's the fact that not only does the Creature gain human-like skin and lose the ability to breathe underwater, but on land he also becomes several inches taller because he's being played by a different actor.
Apart from that, there's some mildly worthwhile stuff here.
Firstly, there's character work among the scientists. Jeff Morrow is disturbed and not doing a bad job of portraying this. Leigh Snowden is playing his adventure-seeking wife, who's trapped between an abusive husband, a sympathetic colleague and a sexually aggressive jerk who won't take no for an answer. Incidentally the latter's played by someone called Gregg Palmer, who also played minor roles in Star Trek and a couple of 1960s Doctor Who stories (The Tenth Planet, The War Games). This turns into the film's most important dynamic, as almost all the males (including the Creature) in their own ways focus on Snowden.
Because of all this, I don't know if it's even a plot hole that Snowden was brought along on the expedition in the first place. Obviously it's ridiculous and makes no sense, but maybe that's the characterisation of their marriage?
Then there's the Creature. I think it's a retrogressive step to make him land-based, but I can forgive it in this one movie because the whole point's to explore the idea of forced evolution. It really helps that it's the last in the series, by the way. This film would have become pointless if they'd just hit the reset button for a fourth instalment, but as it is this becomes the end of his story and even speculate that his return to the sea at the end might be a form of suicide. We've been told that if he goes back underwater, he'll drown. Anyway, there's something of Karloff's Frankenstein in this landlocked, lumbering Creature with its bald head and boiler suit. (They make it wear clothes.) He's quite a powerful image as he walks around, kidnapped from his natural element and no longer able to return, while his rampage at the finale is pretty impressive. Now that's what I call a trail of destruction.
There's also quite a good shock moment when we first see him. He's merely swimming past the camera, but he still startled me.
Some of these are good elements. I think they've been put in a rotten story framework, but equally I'm sure many people would see all the technobabble as mere window-dressing and take a different view of the film. I can't imagine anyone falling in love with it, though. It's a bit boring and it's not as attractive to look at as even the second film, although the director clearly enjoys looking at Snowden. Unlike its predecessors, it wasn't in 3D. Maybe that made a difference? Perhaps directors put more effort into a 3D film's visuals, which makes it look better even if you're only watching in 2D? I can imagine people enjoying this film... but personally I thought it was nearly dead in the water.