When Brenner and Violet are drinking wine in the closet, they are clearly inebriated. When they come out of the closet, they're completely sober, and each of them 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, a "Dojo Quest" poster is in the background. The strap on Lady Lisa's shirt starts at her left shoulder and goes across to the right. Near the end of the film, the strap goes from her right shoulder across to the left.
During the meeting of the National Security Council, Admiral Porter (Brian Cox) is wearing Naval Aviator wings (pilot wings with one anchor). Later in the movie when Ludlow and Sam are meeting the Navy SEALs, Admiral Porter is wearing Naval Flight Officer wings (two crossed anchors)
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. In the second, he pops a wheelie before he approaches the car.
When Cooper is watching news footage in London, it shows him and his wife in a cafe being the sprinkle monster. The Sky News footage says "live" in the top right corner, but Cooper was in London at the time.
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 installing the Sony TV, due to health and safety there is no way one person could install an 85 inch LCD TV on to a wall mount above head height due to the weight and size of the screen.
When Brenner and Violet arrive at the White House. Violet is told to go into the Situation Room while Brenner is told to go into the Oval Office. Its implied that both rooms are right down the hall from each other. Both the Situation Room and Oval Office are located on two different levels of the White House.
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). The film 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. 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. Film is a two-dimensional medium (3D is an illusion created by two 2D rails), so technically the movie has no voxels.
Arcade games in 1982 used CRT screens, but the games shown in the beginning have LCD screens (no curvature, no scan lines, no phosphor persistence). That was a deliberate choice by the filmmakers, because CRT screens are very difficult to film.
When Brenner and Professor Iwatani encounter Pac Man, they are are shocked to discover that "Pac Man is a bad guy," even though they had been preparing for hours to fight, heard about Pac Man's earlier attack, and arrived in vehicles designed for fighting Pac Man. It's possible that they didn't really believe in a bad Pac Man 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 running around, but no video game characters are chasing them around.
In Ludlow Lamonsoff's first scene, the actor's blond hair sticks out of the front of his wig, on right side.
When Brenner and Will first meet Ludlow as kids. Ludlow is wearing a wig and you can see blonde hair above his right ear.
In the opening scenes, set in 1982, characters discuss their favorite celebrities. Madonna is among those mentioned. Madonna had started her career by 1982, but wasn't yet a celebrity.
In 1982, a video game contestant wears a Karate Kid-style headband and uses the crane kick stance. Le moment de vérité (1984) was released in 1984.
Corporal Hill's uniform 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), but the beret badge is incorrect, and the beret should be sand, not green. Additionally, the camouflage pattern on Hill's uniform was completely phased out by 2013.
The coordinates given for the Centipede attack (51 30' 29", 0 9' 42") are right in the middle of the River Thames. During the attack they are in Hyde Park, about 17 miles from the given coordinates.
In the street scene right after Ludlow and Lady Lisa come face to face for the first time, the traffic lights shown are the common in Canadian cities like Toronto.
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 video game character, but an alien invader with the form of the video game character. Even Iwatani tries to convince Pac-Man that he is not evil.
When Brenner is first let into the Van Patten household, Matty mentions the Playstation 4. When Brenner begins the install of the TV, a Playstation 3 is to his right.