Continuity mistake: Towards the end of the movie, Halliday shows him the self-destruct button. When the van gets hit, he slams into the wall, almost pressing it. Before the van is hit there are controllers hanging on some wooden hanger right under the button, but when he trips and his hand is on top of the button, the wooden hanger, and the controllers magically disappear. (01:59:35)
Continuity mistake: After using the Cataclyst to wipe out everyone, Sorrento exits his gaming rig, falling to his knees and removes the groin section, handing it to the guy as they walk through the door. Next shot we see Sorrento with the piece back in place. In fact, he runs his hands over it as he walks past.
Continuity mistake: During the battle on Planet Doom, Art3mis jumps into the DeLorean to tell Parzival that they're "playing Adventure." She jumps in through the windshield. When the shot changes, the hole in the windshield is now larger.
Other mistake: When Wade is explaining his past at the beginning, he says he was born after the corn syrup droughts, after the bandwidth riots, after people stopped trying to fix problems and just tried to outlive them. Then he says his parents didn't make it through those times. So, how was he born?
Revealing mistake: Just after Wade gets threatened and his home is about to be bombed, he leaves his van trying to call his friends. After this shot, the camera pans over a load of scrap cars. Whilst the movie is meant to be set in America, at least 3 UK registered cars are visible in amongst the scrap cars, still wearing their UK plates. These 3 rather unremarkable cars, a Ford Mondeo, Fiat Punto, and Ford Fiesta Courier van, are unlikely to have ended up in the US.
Suggested correction: Though unlikely, not impossible. This is a future scenario and it's not far fetched to think that some economic crisis prompted people to buy import cars and then never given US plates. Or they were imported for parts. Or some UK workers using their own car.