The obvious use of a stunt double when Trip flips in the air trying to catch the "ball" while playing the game in the desert.
One of the cameras has a dust spot on the lens around 23 minutes during Archer and Trip's trek through the desert.
Archer and Trip mention several times that they took an advanced desert survival training course when they were in Starfleet Academy. Yet they aren't following one of the most important lessons about surviving in the desert: you are supposed to sleep during the day and walk at night, traveling during the cooler temperatures at night helps conserve both water and energy.