Revealing mistake: When Doug stops to rest while being chased by the dog, he rests against a thick, heavy tree that wobbles when he leans against it.
Continuity mistake: After falling into the quicksand, Nimon's head and right hand are exposed, but the next shot when Tony and Doug arrive to help, only his head is seen.
Continuity mistake: During Tony and Doug's meeting with Nimon and the Magister, the assistant points his laser gun close to Doug's back, but when the Magister signals to shoot, the assistant is now several paces behind Doug, and there was no time for the assistant to step back.
Continuity mistake: Vokar's assistant brings Tony and Doug into the control room, stopping in front of a dome. The assistant is directly in line with Doug and next to the dome, but the next shot shows the assistant standing further from the dome and towards Doug's left.
Continuity mistake: When Vokar's assistant summons Tony and Doug, they are in a room with very dark walls, but the profile shot of the assistant shows a beige wall behind him.
Factual error: Raul Nimon uses a silencer-equipped revolver during his attack in the tunnel control room. In reality, a silencer on a revolver is useless, as the exploding gases from the bullet discharge (the gun blast) would exit from the space between the cylinder and gun barrel.
Continuity mistake: After the gunpowder in the cave explodes, the same keg of gunpowder is blasted out of position and rolls down twice.
Revealing mistake: The lizard crawling through the jungle in 1,000,000 B.C. brushes against and nudges a heavy tree.
Revealing mistake: The heavy boulder Tony uses to brace himself to save Nimon easily wobbles as he moves.
Continuity mistake: The boxes near the wounded sergeant switch positions after Macchiavelli shoots him.
Continuity mistake: Tony's position instantly changes as he tries to kick Doug off the bridge.
Factual error: One of the Spanish soldiers lights a torch with what appears to be a hand-held lighter. Early lighters were converted flintlock pistols (not yet invented during the time of this episode) and the earliest hand-held lighter would not be invented until three hundred years after this episode's timeline.
Revealing mistake: After the first Native American is shot in the back with the crossbow, the base used to stabilize the arrow in the back of the actor is visible underneath his clothing.
Revealing mistake: When Doug drops the torch on the gunpowder trail, the ignition of the powder is about one foot before the point where the torch is dropped.
Continuity mistake: In the opening scene of Doug and Tony's landing, Doug lands in a bush, but the next shot of the two recovering has Doug outside the bush.
Continuity mistake: After Doug drops the torch on the gunpowder trail, one of Cortez's men grabs and moves the powder keg out of the way twice.
Revealing mistake: The heavy stone table the mask is sitting on in the cave during the fight scene wobbles when bumped by the cast members.
Revealing mistake: The crossbow a Spaniard uses to shoot the elderly Indian is not loaded with an arrow.
Continuity mistake: When Doug takes cover in the cave, Nakamura fires two shots at him without chambering a new round in his bolt action rifle.
Rendezvous with Yesterday - S1-E1
Continuity mistake: After Tony travels, Doug is beside the senator using a machine but in the next shot the distance between them decreases.