The Imitation Game is a great example of cinematic Augmented Reality. I loved this film and, straight after watching it I was inspired to find out more about this interesting period in history. As I quickly found, there are several ways in which this movie improves on history, and several online articles fact-checking it. I'll point you to this one by an authority on Turing, it's very readable and the author agrees with me that the inaccuracies don't kill the movie. Incidentally this movie stars some guy or other as Turing, can't really remember who. He's quite good. I shouldn't wonder if he'll probably be appearing in some more films soon.
Augmented reality should be used for a reason. Adding a Communist spy to Turing's team adds some great dramatic moments in itself, but also dramatises the difficult relationship between the West and Russia during the war. Similarly, making Turing misanthropic rather than just shy, and making him fight with commander and co-workers (in fact he got along just fine with all of them) symbolises the conceptual battle to solve Enigma, which would otherwise have occurred in his head only.
On the other hand Turing's treatment at the hands of the authorities, including his criminalization and chemical "treatment" for homosexuality, is of course true, as is the depiction of his early life, school experiences and crush on his schoolfriend Christopher. Which brings me to a really interesting element of the film - the computer Christopher, built by Turing.
In real life Turing's work on the development of programmable computers was hugely important. He also designed a non-programmable machine called a Bombe, to automate the Enigma code-breaking process. So Christopher is a fictional character, a combination of two separate Turing projects - and fictional Turing's love for fictional Christopher outshines his love for human Christopher, human Joan Clarke or humanity in general. In a way, Turing's fictional mission is to persuade his fellow codebreakers that a computer can fight alongside them and contribute to the war effort. Equal rights for computers!