During the softball game, the scoreboard is shown after runs have been made. Later, just before Vince goes up to bat, you can see the scoreboard in the background show each team with zero runs.
When Amy is showing Zack her ears, she pulls her bangs to the back. She then covers them up again. In the next shot, we see her hair behind her ears, and in the next shot her hair is back in the front.
When Zack enters the cashier's break lounge for the first time, we can clearly see his shirt changes colors throughout the scene.
When Zack is talking to Semi in the security room, Semi's chain moves up and down from shot to shot.
Throughout the movie you will notice that Vince drinks SoBe Nirvana with a turnable green and orange Gatorade cap on the top (which by the way actually fits), however in the scene when the kid in the red shirt is firing tennis balls at Zack and Vince he has a regular Gatorade bottle with saran rap in the holster. It switches to the SoBe Nirvana and then back to Gatorade in his efforts to stop the young boy. When Vince is carrying the young boy to his mother he comes through the ice smoke with a bottle of SoBe Nirvana in his holster.
The scene where Vince (Dax Shepard) scans a bag of dog food from long distance would not have worked since the bar code scanners have a limited range of 1-2 ft. The dog food was also wrapped in plastic wrap and the reflection would have prevented the scanner from picking up anything.
The vehicle that Vince tries to win is supposed to be a brand new 2005 Chevy Malibu. The actual name of that car is Chevy Classic. The vehicle shown in the movie is the 5th generation Malibu sold between 1997 and 2003. The Malibu was completely redesigned in 2004, but the 5th Gen design carried over for 2004 and 2005 to rental car companies and fleet sales and was renamed Chevy Classic.
Vince was able to ring up a voucher for the sale of the POS Honda with his scanning gun which does not have a bar code. He could've only been able to ring up the item by typing in the number on the voucher.
The movie takes place over a course of 30 days. Zack and Vince get stars throughout the month and in the end have a tie. The chart towards the end of the movie has a star on every day for Zack and Vince. Normally, Super Club employees probably would get a day off, but these two are so obsessed with the prize that they have chosen to work on all the days, regardless.
When Amy is first walking into Super Club her hair is blowing back and you can see her ears and they are normal size. Later in the movie we learn that Amy was born with over sized ears and when we see them they are really big.
In one of the opening scenes, there is a large overhead shot of all the registers. You can see Vince, working in register one, but if you look at register seven, you can see Amy working as well. This scene is supposed to take place the day BEFORE Amy transfers to the new Super Club. The rest of this scene is shown later in the movie after Amy has been working at Super Club for a few days.
Some of the computer-generated tennis balls in the missing child scene disappear in mid-air or shortly after hitting the ground.
Near the climax, two shopping carts are visible with the words Costco Warehouse on them. Though filmed inside a Costco, the film was set in a fictitious "Super Club" store.
The movie takes place in a store called Super Club yet we can clearly see products with the Kirkland label on them. Kirkland is exclusively a Costco brand.
When Vince and Jorge are sitting in the POS Honda, Vince states that the car has 33,000 miles on it. Jorge mentions that the odometer had flipped twice, and Vince says "Exactly, 233,000. All highway". A few seconds later, the camera shows the odometer reads 84,330.
When Zack tosses the Cashier's Lounge key into the trash, it says "Employee Acess Key". "Access" is misspelled.
When the guys are in the club house (at about 16:30) and Vince is showing Amy around for the first time, Russell begins a funny tirade about Vince being the "Alpha Male of the Store" and proceeds to give Zack a hard time. When Russell says, "Oh Box Boy...you're like the little hairy nut-sack of the field mouse; swinging back & forth..." Andy Dick (Lon) breaks character and starts laughing. As Russell continues, Andy Dick gets back into character only to lose it again before the scene cuts.
When Zack first becomes cashier and begins checking out his first customer, a few of the items on the conveyor belt clearly show the bar code on the side facing the viewer. Zack then proceeds to check some of these items with the scan gun and these items 'beep,' while it appears the bar code was left untouched. In fact, "club packs", such as the Ramen Cups, do have bar codes on three sides, so there was actually a bar code facing Zack. But when he scans the bags of potato chips, he scans the upper right of the bag, while the bar code is clearly at the bottom right.
When Zack is setting the coffeemaker, he turns it on to start brewing immediately and sets its clock to brew the coffee at the desired time, however there is a "delay" print on the coffeemaker's display which a light would turn on if it was set. Also the "on" was set while Zack is setting the clock, but the next morning, it is not set.
When Vince is learning to try and skate to impress Amy, right after he falls and Jorge runs over to him, Vince starts coughing, but his mouth isn't moving.
In many of the shots in which Vince is scanning and ringing up items, the beep (indicating an item has scanned) is not in sync with Vinces scanning. In one scene the beep sounds while Vince has the product up the air throwing into the box. This happens several times.
At the end of the shopping relay, Vince rolls a tire down to Jorge. When Jorge picks it up and scans it, he randomly points the scanner laser at the tire label, not even coming close to the bar code, yet the tire rings up anyway.
During the middle to the end of the film, the microphone is clearly visible in quite a few shots in the top of the frame. Watch the top of the frame while they are in the warehouse and once or twice in an outside shot.
At the end of November 3rd when the 3rd gold star is put up, Zack says he still has 29 more days to leave a mark, for winning employee of the month. This would result in a 32-day month, which is non-existent of course.
When Vince is trying to scan the dog food, it has damage to the bar code on the front of the bag. Those bags have multiple bar codes on them (as proved by the attempt of the character to scan a bag on the shelf using the side bar code) and Vince would have known this and simply flipped the bag.
When Russell, Lon, and Iqbal try to enter the "club house" in the steel only to find it had been filled in, Russell says that only four people (himself, Vince, Lon, and Iqbal) know about the "club house". In reality, the forklift driver that lifts them up to it would be a fifth person.
Neither Vince or Zack bring a dustpan with them when they are racing to get to the spill area to clean it up. They just bring a broom.
During the final competition, Vince and Zack are presented with an abandoned cart and told they must put all the items back. No retail store would train their employees like this. First, there is no way of knowing right away if the cart is actually abandoned, or if a shopper left it there to come back later for it. Secondly, an employee would never be told to take time to re-stock shelves while a customer was waiting back at his or her checkout stand.