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 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 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.
After Zack gets his first gold star and a date with Amy, he goes home and talks to Iqbal on the phone before picking Amy up. Zack has significantly more facial hair while on the phone than he did that day in the store and more than he has when he's out with Amy later that evening.
After Zack puts an ice pack on his head (after hitting his head on the pallet) he tosses the ice pack aside as he leaves the room. In the next shot he has the ice pack in his hand again and then tosses it on one of the checkout counters.
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 takes Amy up to the "box boy lounge" on their first date, in the close-ups you can see the bars from the fork lift that takes them up. In camera shots from further away, there is no fork lift beneath them and therefore no bars visible.
During the check stand ring off, the store lights are clearly turn off except over the cash registers. This is seen when the two are first running in the dark with the tires and while they put other items back on the shelves. However, when the two are finished putting their items away, the shot of them hitting their carts together clearly shows the store lights on. The lights stay on during that sequence until the two run back with the new tires, where the lights are off again except over the registers.
When Zach and Vince are trying to get to the "Missing Boy" shooting the tennis balls you can clearly see inside the tennis ball machine that there are no tennis balls. The next shot of the boy there are more, then the shot after that with him there are even more balls.
The positions of the golden stars in the chart change throughout the movie. For example, the November 3rd star was placed upside down at first (1 point facing down), but in future views of the chart, it is upright (2 points facing down).
In one scene near the beginning of the movie (when Zack is skating around), there are Turbo Tax software packages on display for sale in the store. This movie is set at the end of October/early November and Turbo Tax isn't sold until the beginning of January.
When Russell goes to Human Resources for the file on Amy, as the Human Resources person pull out the folder, the tab is on the left. On the close-up, the folder has flipped over and the tab is on the right (with Amy's name on it) and then back to the long shot where the folder has flipped back over with the tab on the left.
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.
When Vince is announced as the winner of the car and gets up from his chair to accept the car keys, Zach is sitting slouched to his left, and Zach raises his hands to clap reluctantly. In the next shot, Zach's arms are down on the chair armrests, while in the next he is reluctantly clapping again.
Before Zack decides to start trying for employee of the month, Vince has 11 gold stars on the chart, later on in the movie after the softball game, Semi adds the 11th gold star to Zack and Vince now only has 10 gold stars.
When the lady is telling Dirk that Zach is a good employee there is a woman in a purple shirt walking behind them into the store. When she goes to point out who the employee is, the lady disappeared behind Dirk.
When the "guys" are in the "box boy lounge, and they are talking about Amy's past there are drink cans on the table. In one shot one of the cans is bent and laying on the table, however in the next shot it is upright and unbent.
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.
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 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 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.
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.
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.