This isn't how it works Disliking a movie due to historical inaccuracies is one thing. If this is your only issue, the movie in question may be fine as a work of fiction, just not as a record of history. But here's the thing. I don't know anything about Turing's personal life, nor about the details of how encryption played into WW2. And yet, based mostly on having a degree Computer Science, I can immediately tell that this isn't how it works. This isn't how any of this works. It's not that the movie fails to tell the true story; it fails to tell a *plausible* story.
Here's an example. Turing tries to crack the encryption machine Enigma and builds his own machine to do so. Once started, the machine just keeps running until it cracks the code, without providing intermediate results. If this takes too long, all you can do is stop it manually.
But that is just not how it works. No-one does engineering that way. If you write a big piece of code, it's going to have bugs. You have run parts of it and get intermediate results to find the bugs. Even if it's bug-free, there just is no reason not to add something indicating progress. That's not hard to do, and moreover, we see in the movie that Turing didn't know how long his machine would take, so intermediate results would be extremely helpful.
"Alright," you say, "but that's just a detail, and it's not even important to the story." Fair enough. Here's a more important case. After the team fails to crack Enigma for a while, some random person in a bar mentions that messages encrypted with Enigma often start the same way because people use recurring phrases to open letters. This provides them with a way to restrict the search space, and they crack Enigma on the same day.
Again, this isn't how it works. To elaborate: it certainly is true that knowing things about the plaintext could be extremely helpful, so good job on that. But the fact that no-one in the team figured this out after months of working on the problem is completely asinine. This is basic stuff. Of course the plaintext distribution isn't uniform; messages aren't a random sample of letters, and any capable cryptographer would consider that immediately. This is the kind of the first things you would think about, and I mean that literally. If you made a list of what properties to exploit, that would be one on the top of the list.
I've singled out these two points because they're fairly objective, but they're really just a symptom of a bigger problem, which is that the movie evidently doesn't understand cryptography, computability theory, or even basic engineering -- and as a consequence, Turing is not a plausible depiction of a highly intelligent mathematician. He often says that things are too complicated for others to understand, but when he does talk about technical stuff, it's usually pretty basic, and what's worse, it's often off-topic. The ugly truth here is that neither the Turing Machine nor the Turing Test have much of a connection to cryptograhy. The Turing Machine is theoretical model that is capable to perform arbitrary computations given unlimited time, which makes it useful in formal proofs about what is and isn't computable -- where 'computable' always means 'solvable with definite, explicit rules in a finite number of steps'. However, its runtime is comically awful (it requiers thousands of steps to multiply two 2-digit numbers), so it's utterly useless on any practical problem. It's pretty telling if you watch the scene where Turing is asked about his paper; he doesn't say that the machine is the Turing Machine (presumably because that would just be too blatantly false), but he also doesn't make it clear that it's a different things, so you're sort of left with the impression that the two things are connected. They're not. I don't know what the machine did (the movie doesn't tell me), but I can promise you that it has no meaningful relationship to the Turing Machine. It's honestly just really bizarre that the movie hedges so much on that point.
And the Turing Test? Well, the Turing Test is a philosophical thought experiment about when AI reaches human-level. (It's probably something that Turing got wrong, too, but that's beside the point.) How is that related to cryptography? Unfortunately, not at all. My guess is that the script writer just wanted to have the Turing Test in there because it's the most famous idea associated with Turing, so they just did it even though it really doesn't make sense. It gets away with it by being very vague, so that all you remember is a bunch of buzz words without anything too concrete to be wrong.
On the other hand, the movie doesn't tell you how the Enigma Machine actually works, and that's kind of a shame. I've once had to implement it for my cryptography class as just one exercise on the biweekly exercise sheet -- point being, it's not that complicated. Take three minutes and a nice visualization, and you can explain to normal people what the machine does. Wouldn't that be better than hinting at unrelated topics without ever saying anything concrete? (I notice myself getting more annoyed with this the more I think about it. The only reason not to tell you how Enigma works in a movie about Enigma is that the movie thinks you're too stupid to understand how it works, which is kind of insulting.)
Then, there's Turing's personality. Here is where I'm speculating; maybe he was like this. But I honestly doubt it. A lot of people have this streotype in their heads that the smartest mathematicians are the worst about communicating their insights, but I think the opposite is true in most cases. If you understand a subject unusually well, you're also better at explaining it in simple terms. There are exceptions to this, but given how unreliable this movie is, it seems more likely that Turing was nothing like this and the script just wrote him as the stereotype because that's what lazy writers do. Also, just keep in mind that he's a professor, which means he's working at a University. Teaching basic material is part of his job.
Watching this for the second time made me think about the Queen's Gambit. Both shows (I'll just refer to this movie as a 'show' to have a common name) are about a person with an extreme genius; in one case it's math, in the other it's chess. Furthermore, both shows have pretty positive reception. However, the Queen's Gambit is great both in terms of depicting what a genius is like and in terms of the chess it shows. Here is what it gets wrong: In episode 2, people talk during tournaments, which is not allowed, and (also in episode 2), there is a part where Beth says "I don't have to move the Queen", when that makes no sense in the position. (Very likely someone messed up "Queen" and "King" there, because "I don't have to move the King" would have made sense.) As far as I know, that's it. Everything else in the entire show is spot on; the games are all based on real games played by extremely strong players, the commentary all makes sense, and the players can do the things that real chess geniuses can really do, like playing entire games in their heads and playing several games simultaneously.
But here's my point -- looking at the two shows side by side suggests that most people don't notice these things. They don't see the difference between a supposed genius who doesn't build a progress report into his machine on the one hand, and a realistic chess-prodigy on the other. They don't see the difference between a show that would get an A and one that would get an F in terms of technical accuracy. People probably just like the Queen's Gambit for other reasons, and its hidden qualities are incidental. Similarly, people like this movie without realizing that it's all empty talk and no substance. Even the people who give it flag for historical inaccuracies mostly criticize that it *didn't* happen that way, not that it *couldn't have happened* this way because it's just not how any of this works.
So yeah. In conclusion, I'd say this movie sucks and also watch the Queen's Gambit.