When Brenner and Violet are drinking wine in the closet they are clearly inebriated. Then when they come out of the closet, they're completely sober, and proceed to each drive a vehicle to the White House.
The sword on Ludlow's neck changes position in two shots.
When Lamonsoff takes Brenner to his grandmother's house, there is a "Dojo Quest" poster seen in the background. The strap on Lady Lisa's shirt starts at her left shoulder and goes across to the right, while near the end of the film, the strap goes from her right shoulder and goes across to the left.
In the opening credits, Young Brenner, on his bike, passes the same parked Camaro twice. In the first shot he pops a wheelie as he's passing it, and in the second, before he approaches the car.
When Brenner arrives to do the AV install, one of the items he is told he will be installing is an 85 inch big screen TV, however when we see the TV it is no larger than a 50 inch.
When Ludlow is in his basement talking to Sam, he correctly mentions that a base was attacked by "Galaga", but points to a picture of the white protagonist ship from the original Galaga (1981) video game. The actual Galaga (called a Boss Galaga) is the main ship the aliens use, not the white Fighter Lud pointed to. That ship is called a Gyaraga or simply "Fighter".
When Brenner is first let into the Van Patten household, Matty mentions the Playstation 4. However when Brenner begins the install of the TV, you can see just to his right a Playstation 3.
When Cooper is watching news footage in London, it shows him and his wife in a cafe being the sprinkle monster. On the sky news footage it shows live in the top right corner but it couldn't be live as Cooper was in London at the time.
In exchange for helping the Arcaders, Eddie Plant asks to be exempt from taxes and gives the example of a tax when buying gum. Sales tax is levied by the states. The US President would have no authority to grant such a request.
Several of the game figures that the aliens use for their patterns are from games released after 1982, such as Tetris (1984), Arkanoid (1986), and Paperboy (1984). However, it is never claimed that the probe was launched in 1982, only that it included footage from that year. It could've been launched years later and included footage from later years too. Long delays aren't that rare in NASA. Also, the aliens could've updated their data by picking up Earth transmissions after the probe got their attention.
Although the movie is titled "Pixels", the attacking aliens are actually composed of voxels. Pixels are 2D and Voxels are 3D. However, it is never claimed in the movie itself that aliens are made of pixels, and the name of the movie is just a name, not a statement of fact. Of course, the movie couldn't have been called "Voxels" in any case - this term is too obscure for marketing purposes (see Trivia section for details). Anyway, since the movie itself is a two-dimensional medium (3D is just an illusion created by two 2D rails), technically there are no real voxels in the movie.
Arcade games in 1982 used CRT screens, while the ones shown in the beginning have LCD screens (no curvature, no scan lines, no phosphor persistence). This was not a mistake, but a deliberate choice by the filmmakers, because CRT screens would be very difficult to film. See the Trivia section for more details.
Upon encountering Pac Man, both Brenner and Professor Iwatani are shocked to discover that "Pac Man is a bad guy," even though they had been preparing for hours to fight Pac Man, heard about Pac Man's earlier attack, and they arrived on the scene driving vehicles designed for fighting Pac Man. However, it's one thing to hear about a bad Pac Man and another is to actually see the carnage up close. Perhaps they didn't really believe in a bad Pac Man because they didn't want to, until they saw it with their own eyes.
The main characters are explained to be perfectly suited for the task of fighting the aliens because of their years of practice with classic video games. Then how do handle firearms so well and race cars through a city? Some arcade games require the use of a physical gun or a steering wheel, so they are supposed to have those skills. The premise of the movie is that those skills are transferable to the real world. In any case, they are not using real guns, but special "light shooters", which are far more similar to an arcade weapon than a real one, so it makes sense. As for the cars, driving a car isn't a special skill and they aren't even doing anything particularly special with those cars.
When Max Headroom is talking with the heroes, the people in the background are still running about, but there is a noticeable lack of any video game characters chasing them around.
At the beginning where Will is cutting the grass, you can see he is totally faking it- he doesn't have to scream as he talks while the mower is supposed to be running, and you can see he is not cutting any grass.
When you see Ludlow Lamonsoff for the first time in the beginning of the movie you can see the actors real blond hair sticking out of the front right side of his wig.
In the opening scenes, set in 1982, characters discuss their favorite celebrities. Madonna and Samantha Fox are among those mentioned. Both women had started their careers in 1982, but neither was a celebrity.
In 1982, a video game contestant wears a Karate Kid-style headband and uses the crane kick stance. The Karate Kid (1984) was released in 1984.
Corporal Hill wears a uniform that is out of date. Modern British Army uniforms have their rank tabs on the front of their jackets not on the shoulders. The credits claim that the character is "SAS" (Special Air Service, a British Special Forces Unit) - the beret badge is incorrect for SAS and the beret is green, SAS berets are a 'sand' colour.
Additionally, the camouflage pattern on Hill's uniform is incorrect. While the DPM (Disruptive Pattern Material) pattern shown was used by the British military, it was completely phased out by 2013 in favor of MTP (Multi Terrain Pattern), a Multicam derivative.
The coordinates given for the Centipede attack, (51 30' 29", 0 9' 42") are right in the middle of the River Thames, yet during the attack they are in Hyde Park roughly 17 miles from the point stated.
In the street scene right after Ludlow and Lady Lisa come face to face for the first time, the traffic lights shown are the ones used in a Canadian city like Toronto, where the movie is filmed, and not for any U.S. city.
In all of the video game battles, the alien attackers play the in-game opponents, while the gamers play the "player" role that they would have in the actual arcade game, exception for Pac-Man. For Pac-Man, the gamers play the ghosts, which never happened in the arcade game. Furthermore, despite having no advance warning, the gamers are not only specifically prepared to play Pac-Man, they have four customized Mini Coopers ready to go, complete with "cheat codes" for the ghosts.
It appears that all the heroes did forgot that Pac-Man is not the real videogame character, but an alien invader with the form of the videogame character; even Iwatani tries to convince Pac-Man that he is no evil.