Factual error: When Ray leaves his wife Gina and his car is hit by the truck he should still be in England, but when he is being chased through the streets he is in South Africa, the cops in the car are not in English police uniforms or vehicle, police livery is incorrect, and all vehicles have South Africa plates, not English number plates.
Factual error: When first sucking a bullet from the wall into his gun, he then opens the previously empty magazine to find the bullet. Given he didn't work the slide (forwards or in reverse), the round should not be in the magazine, but in the gun's chamber ready to fire. (00:14:00)
Factual error: The plot's main conceit hinges upon coders, the art department, and the user-end network team constantly working live at the same time in the same room, as well as developers actively writing code, rebooting servers, and chasing players in-game to get rid of problematic players. No real game company could operate this way. Game content patches wouldn't change the network experience, and in-game aesthetic changes like the ones they make in seconds would require weeks if not months of development.
Factual error: Babe Ruth is shown batting right-handed; in reality, he batted left-handed.
Factual error: After Maya Peters is brought into the recompression chamber because of an injury, the timer is shown counting down by hundredths of a second and skips from 1 to 0 without showing 0.99-0.01. (01:24:30)
Factual error: The pilot is flying from the left-hand seat. Helos are flown from the right side. (01:23:00 - 01:25:00)
Factual error: 1. Turntables used by radio stations have no repeat play function; they are strictly manual operation. 2. Even if they did, continuous play of one 45rpm record would have eventually elicited a skip, and later the complete wearing through of the vinyl by friction of the needle. (01:25:40)
Factual error: Trevor was driving ECTO-1 at over 60 mph. Podcast was driving the remote car and it was pulling away from ECTO-1. There is no way that the remote car could be going faster than ECTO-1, unless it was souped up, which it didn't appear to be when looking at it.
Suggested correction: There are plenty of RC cars on the market right now that anyone could buy that are capable of going 60+ MPH (the fastest can hit about 100 MPH). And if you take them apart, they don't look "souped up" at all. They just look like regular RC cars inside. Components don't have to look fancy to function fancily. You also have to account for the fact that the movie is highly fantastical, so there's no telling what kind of technology the RC car uses... for all we know, it could be nuclear-powered like the proton packs.
Factual error: Joel is using a ham radio set to contact his old colony. A shot of the radio set shows it is set to "CW", which is Morse Code, but he is using voice. And the strength meter is on zero. It should be showing the signal strength. (01:24:00)
Factual error: Real-life Martina Franca is a town in Puglia, at the "heel of the Italian boot." The town shown in the film is the famous San Gimignano in Tuscany. And when Holly "defects" in order to go to the Hill of Tara, her departure point, as seen on Foaly's observation monitor, is the real-life location of San Gimignano. (00:35:50)