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.