Race puts the sentry at Post #5 in a choke hold, then shoves him head first off the guard tower into the swamp. Later, when Gen. Fong orders all guards to stop the Quests from escaping, the guard at Post #5 is shown knocked out on the floor of the tower.
When Lt. Singh kidnaps the boys, he closes the hotel room door behind him. When Dr. Quest switches his view-com back to the hotel room, the door is closed. When Dr. Quest and Race return to the hotel room, the door is closed. When they play back the recording of the kidnapping, the door is left wide open.
Lt. Singh's clothes are sullied from his car wreck, but while Dr. Quest questions him and bandages his arm, the dirt and grime on Lt. Singh's clothes disappear. The grime returns when Benton is done questioning him.
The Quetong city map mounted behind Hadji and Jonny in the Commissioner's office spells the city's name as "Quetung" - a 'U' instead of an 'O'.
China's population was 725,380,000 in 1965, yet during Race and Benton's daytime helicopter chase through the city, there are no people at all on the streets.
When Race and Dr. Quest are in the helicopter chasing the Lieutenant, you can hear Race say "I see him" but it is Dr. Quest's lips moving.
When Race and Dr. Quest (in their helicopter) tail Lt. Singh (in his convertible), one shot has the helicopter flying after the car down the city street between the buildings at the second story level. Not only is that dangerous, improper and possibly illegal, it in no way can be considered a discreet way to follow anyone (yet Race and Benton are surprised when Lt. Singh spots them following him).
By the time General Fong shoots Sentry #1, his boat has floated to the other side of Sentry #1's tree. His bullet would either have to go through or around the tree to get to Sentry #1.