Plot hole: When the Griswolds are at Wally World, supposedly the only people there are the guards. Who operates the rides for them?
Suggested correction: The guards also knew how to operate the rides.
Original mistake is correct. There were only 2 guards. 1 they kidnapped. The other they left lying like a dog until he could call the police. Therefore, there was nobody to operate the rides. Besides amusement parks don't train security to operate the rides.
Plot hole: Clarence Beeks plants the angel dust on Winthrop at the Heritage Club, which is discovered by the police at the station. Though he's out on bail, Winthrop is still facing years of jail time if convicted. But nothing again is mentioned about it for the rest of the movie, nor is he trying to clear his name.
Plot hole: During the supercomputer's destruction, the 3 electrical probes that are sending lightning to the overhead pylons to draw electricity from them are no longer flashing. So where is the electricity coming from to sustain the computer's lighting system as the fluorescent tubes are still working?