Alonzo Church first came up with Lambda Calculus, an obscure branch of mathematics that deals with the manipulation of symbols. Pretty much at the same time, Alan invented the (Universal) Turing machine, an ingenious construct that manipulates symbols with programs. Together, they formed the Church-Turing Thesis which basically defined how a theoretical computer can solve problems. This remained academic until John implemented Turing machines with the famed von Neumann architecture that led to all computers today.
Alan Turing laid the foundation for pretty much all computational devices today to exist. Oh, as the main theme for this movie, he also broke the German Enigma machine that helped win the war. Without him, millions more would have died, history might have been completely different than how it really became, and you wouldn’t have a cell phone in your pocket. Alan Turing should have been celebrated and revered as a man who changed the world for the better. Yet, he killed himself after being prosecuted for being a gay.
It was a wonderfully acted movie that did not bore people with how the Turing machine was made. Instead, it focused on the man, his intellect, and character. It was simply an additional bonus for a computer nerd to enjoy an obscure bit of scientific history that made it to the big screen.