Other mistake: In the first carousel one of the female contestants is obviously pregnant. But in the film babies aren't born from a mother but through artificial means.
Suggested correction: I just watched the scene on YouTube and didn't see anyone who was "obviously pregnant." Who are you referring to?
Plot hole: In one of the late scenes Logan is interrogated by the mainframe computer, and is guarded by two other sandmen. No one in the city is allowed to be over thirty years of age, yet the guards are at least in their late 30s or early 40s.
Suggested correction: How do we know how old they are? Just because someone may look like they're in their 40s doesn't mean they are. I have several friends and coworkers who look older than their actual age.
I also thought the guards looked old. Yes, maybe they were 29 but since they had a minimal role, it wouldn't have been difficult to go with actors that actually looked like they were in their 20s.
Continuity mistake: In the ice cave, Logan and Jessica take off their clothes and put on animal skins. When they run out of the storage chamber where they saw the frozen cadavers, they drop the skins and are fully clothed.
Suggested correction: Before that scene, they are shown getting dressed. If you saw this on television, they may have cut the shot because of some brief nudity.
Stupidity: Why is it that runners wait until their 30th birthday to run, when they'll most likely get caught? It would make more sense if runners tried to escape to sanctuary weeks or months before their last day. This way, they could meticulously plan their escape without drawing attention to themselves.
Suggested correction: That wouldn't be particularly advantageous for runners. The computer system monitoring the city knows when someone is running regardless of their age and will dispatch the Sandmen to eliminate them. People who choose to run only do it as a last ditch effort, believing they will die on Carousel anyway so running is a risk some are willing to take. In the meantime it would be preferable to live out their guaranteed lifespan and enjoy the pleasures afforded to them by living within the city.