When Zack tries to convince Delaney to be the producer on the escalator in the mall, the alternating close-up shots of Delaney and Zack show that they are already at the top of the escalator by the end of the conversation. However, when they show the shot of Delaney trying to decide before tossing Zack a bundle of money, they are still a few seconds away from the top.
When Zack and Miri get their name tags from Betz, Miri places her name tag a few inches from the top of the dress. However when it cuts back to them, her name tag is higher up and on an angle. Zack's name tag also changes position between shots.
When Miri and Zach are in the car on their way to work they get out of the car and Miri doesn't close the door, and Zach comes around the car and gets in.
When we first meet Deacon, he's playing hockey and hits a player and is sent to the penalty box. In hockey, goalies do not serve their penalty, another player serves it for them.
When Zack and Miri come home from their high school reunion, Zac has a trophy in his hand. There is no reason explained in the DVD cut why he has a trophy. However, in the deleted scenes part of the DVD, there was a scene where Zac and Miri won a trophy for being the people who lived the closest to their high school as opposed to the trophy for people who moved the furthest away from their high school and it is pointed out Zac and Miri live across the street from their high school.
Zack and Miri are supposed to live in Monroeville, Pennsylvania, yet right next to the coffee shop is a Hollywood Tans. Despite claims to the contrary, there are Hollywood Tans all over the US - including in Monroeville, PA.
The shots of the auditions were actually set in a playhouse that was originally a much longer scene that was meant for the full feature film. Due to time restraints the scene was cut out and just used as an internet trailer.
When Zack and Miri are in the coffee shop, Miri talking about she is unwilling to sleep with a stranger. You can see a coffee pot half filled with coffee. In one of the scenes (at the end of this shot) you can see the coffee vigorously shaking, as is its just been put on the coffee stand, but the seconds both previous and after to this it's completely stable. This happens because Zack had been leaning back against the counter and when he pushes off it jars the counter slightly and disturbs the coffee in the pot.
In the trailers, when Delaney (Craig Robinson) says the line "Han Solo and Princess Leia ain't never had no sex in Star Wars," Lester (Jason Mewes) can be seeing mouthing the line along with him. This is reported to be an intentional reference to a famous goof in Star Wars: Episode V - The Empire Strikes Back (1980) where Harrison Ford can be seen mouthing Carrie Fisher's line.
When Zack is shown the final film, it contains below average three sex scenes. However, they spent all night until 6 am shooting videos, they must have much more shots to edit from.
When Zach and Miri are leaving the bar (the West End Cafe) they are shown walking down the street. In Reality, the street and direction they are walking down actually leads to the West End Cafe.
In the beginning, when Zack and Miri are driving to the mall, Miri pulls over by Ralph's Army Surplus. If driving this direction, you would be driving away from the mall.
(At 14.30) There is a scene in Zack and Miri's apartment where they're sitting around their trash can fire. Zack complains that they're living "like a couple of STENO bums" instead of "STERNO bums".
After excitedly wrapping up the first night of filming, Miri calls Stacy "Stacer" (likely getting her tongue twisted when acknowledging "Stacey, Lester...").