Worthless drivel, yet somehow enjoyable anyway. So it's better than Abbott and Costello meet the Mummy, then.
I'll address the film's good points first, which won't take long. Firstly, it looks gorgeous. Horse-drawn carriages! Top hats! Camerawork so delicious that you could put it on your wall! I love old Universal black-and-white classics... of which this most certainly isn't one, but it looks like it. It's set in London at a time when Dr Jekyll is transforming into Mr Hyde , suffragettes are campaigning  and the London police force has an American exchange programme and dresses half its officers in the uniforms of French gendarmes . You'll have to forgive the cultural inaccuracies. Nevertheless with photography this delicious, who cares?
-  - Stevenson's novella published in 1886.
-  - Women's Social and Political Union founded in 1903, achieving its goal with the Franchise Act of 1928.
-  - never.
My other favourite thing is Boris Karloff, even though ironically he's not very good. The thing about Karloff is that he's a man of enormous presence and charm who's obviously a highly experienced stage actor, but he never did get his head around cinema acting. That was understandable in 1931. Unfortunately two decades later there are still moments where he's dead-eyed and empty. At first I didn't think his Dr Jekyll even made sense, either on the page or in Karloff's performance, but this isn't a good man in a moral quagmire. Jekyll's just as evil as Hyde, but self-delusional. As he cold-bloodedly makes plans for Hyde to murder his perceived enemies, he's not even aware of his own degenerating mental condition. Admittedly some of this is Karloff just playing the dialogue as it comes without really going deeper, but one could argue that this is just as likely as Stevenson's clear dividing line between the split personalities.
All that said, Karloff's wonderful fun in a role that knows he's the star and allows him every luxury. His Dr Jekyll is an urbane, well-dressed gentleman with impeccable manners and blood on his hands. He's playing Peter Cushing! He also has a tall, impressively ugly sidekick who looks as if he's been a professional boxer for thirty years and a loser for the last twenty-five of them. I liked him too.
Meanwhile Mr Hyde is just an animal, basically the Wolfman with a different make-up job. His face is striking, but unfortunately it's so much bigger than Karloff's own features that in effect it's a completely immobile mask. Why hire the greatest physical performer in the history of horror cinema and then render him anonymous when he's playing the monster? Nevertheless hilariously the British censors gave this film an X certificate, which throws a new light on Hammer's Dracula and Frankenstein a few years later that decade. (It's since been shown on children's TV.)
There's also a curiosity in a wax museum. Among the exhibits are a Dracula and a Frankenstein, the latter of which gets brushed by electrical cables and starts walking! If one were determined to do so, one could thus regard this as another Universal monster mash-up of Dracula, Frankenstein and a Wolfman.
Oh, and why do they pronounce Jekyll as "Jay-kull"? Is that standard in America?
That's all the good. The bad would be everything else, especially Abbott and Costello. This movie came at the rag-end of their career when their best work was behind them, but even so it's shocking how big a gulf there is between their antics and humour. They have a couple of good moments at the 24 minute mark, then a good line at around 37 minutes. That's absolutely it. I'm even stretching it with the word "good", since my actual reaction wasn't to laugh but instead to recognise that at least they'd briefly crawled out of the pit of anti-comedy.
It's baffling. There's nothing even amusing about what they do. They jump, squeal, pull faces and hit each other by accident. That's all they do. I didn't even believe in them as human beings. I can admire Costello's physical work in an abstract way, but he's not particularly trying to create any kind of reality. Even their names don't make sense, since by this point in their career "Slim" is soon going to be the same shape as "Tubby".
However they're not helped by the script, which is like watching a moderate school pantomime. Leaving aside the "was that meant to be funny?" physical gags, just look at the romantic leads. They're likeable. They're excellent, in fact, maintaining the charm of this movie in the face of all reason. They're played by Craig Stevens and Helen Westcott and I've just gone so far as to look up their filmography. Nevertheless their characters meet for the first time at the start of the film, manage a couple of chats between the anti-comedy and then the next day are telling Dr Jekyll about their impending marriage! We haven't even reached the one-hour mark. This is important to the plot. I can accept that. However it would have also torpedoed any other movie beyond repair and it says everything that instead it fits in with the general tone.
In fact, despite appearances there's good acting in this film. The best would be from Reginald Denny as the Inspector, who'd also been Algy Longworth in the Bulldog Drummond films of the late 1930s and whose final role would be Commodore Schmidlapp in the 1966 Adam West Batman movie. Even in his few scenes, he impressed me.
There are also song and dance numbers with pretty girls. In 1953, these would have been risque. Here, they just stop the plot.
This film isn't even "so bad it's good". Its virtues are real, while there's precious little camp factor in its mediocrity. By definition there's nothing so unfunny as failed comedy. Nevertheless the photography, the supporting actors (mainly Karloff) and general charm kept me watching. I can even imagine putting it on again some time. Crucially as usual with the Abbott & Costello horror-comedies it's trying to be a proper Jekyll and Hyde film that happens to star a couple of comedians, so when the latter are a flop (as here) there's still the rest of the movie. Somehow I managed to enjoy this, or at least watch it peacefully, but by any objective measure it's terrible.