Factual error: When Zach and Nomi are talking on stage after Nomi's disastrous experience at the boat convention, Zach places a call to Phil Newkirk. There are several problems with the call: the cell phone doesn't appear to be on (he raises the antenna at the beginning and end of the call, but he never presses an "on" or "off" button); Zach doesn't punch in enough numbers for the call to appear legitimate (too many numbers for speed dial, but too few for a local seven-digit phone number [also, since he was using a cell phone it's unlikely that he dialed a hotel extension number]); and the pauses between his words and Phil's response on the other end of the line are too short to be believable.
Deliberate mistake: When Cristal and Zach's limo pulls up in front of the Club Cheetah, the Stardust is prominently displayed in the background at a close distance to the club. In reality, the Cheetah is a popular and well-known strip club in Las Vegas. People such as myself who have actually been there know that when looking at the Cheetah from the angle seen in the film, there would be no possible way the Stardust could be in the background (in actuality, the I-15 highway would be in the background, not the strip). (00:22:35)
Continuity mistake: When Cristal and Zach go to the Club Cheetah to watch Nomi dance, Nomi comes out on stage wearing black lace-up heels. Then when she storms off the stage, apparently upset by Cristal's presence at the club, she's wearing Mary Jane-style heels. Then when she's giving Zach the private dance with Cristal watching, she's wearing the lace-up heels again.
Audio problem: When Nomi is dancing at the Crave Club with the bouncer, she kicks him for making a suggestive comment and the bouncer stumbles backward into another guy on the dance floor. The bouncer tells the guy to "be cool", and the guy responds with "you be cool, buddy", but as we hear him say this, he's already punching the bouncer and his lips aren't moving along with the words. (00:17:35)
Factual error: In this scene at the end of the movie, Nomi is on the side of the highway attempting to hitch a ride out of Vegas. The driver in the truck picks her up and makes a right. Logically the truck would be making a right onto the highway because that is what we see in the preceding scene, but geographically the street which the driver turns onto is west of the highway and does not have an I-15 entrance. (02:01:05 - 02:02:05)
Continuity mistake: When Nomi is initially talking to Andrew Carver and they are both full length in the scene, there is a large amount of space between them. In the next scene, which is close up, Nomi is inches away from Andrew's face. When she introduces Molly, they are far apart again.
Other mistake: When Molly introduces Nomi to Cristal backstage, Cristal is sitting at her dressing table and Nomi is standing a few good feet away. When Nomi runs out of the room after Cristal makes a rude remark, Cristal comments to Molly that Nomi has "nice nails"; however, it seems impossible that Cristal would've been able to see Nomi's nails from where she was sitting.