Everything:

• Turing wasn't autistic, nor was he insufferable. He was reportedly very well liked among his peers.
• The film majorly downplayed Turing being gay and his gay relationships
• All the drama in the enigma team never happened
• The thing with the not reporting the ship is not a call researchers are in position to make in the first place
• The movie focused a lot on Keira Knightley's character despite the real person not being that close to Turing
• The "breakthroughs" in research shown in the film of looking for patterns in coded messages is the very basis of code cracking, they dumbed it down because they thought audiences were too dumb for the actual breakthroughs.
• They downplayed the horrors he suffered through the end of his life