Visible crew/equipment: Barton is terrified by a plant-like alien floating outside his spaceship window. The Venusian critter might be a heck of a lot scarier if it bore less resemblance to a furry stalk of celery - and if only its puppet strings weren't showing.

Factual error: Barton's ship, we're told, has been designed only to orbit Venus, not land there. Yet he somehow lands anyway - on a planet with atmospheric pressure and broiling temperatures that should have crushed and incinerated him instantly.

Revealing: This 1964 episode is supposed to take place in its own near-future (the late 1960s). But some of the shots in the beginning reveal the use of outdated stock footage. During the parade, there's a close-up of a 48-star US flag, a relic even in '64, as Alaska and Hawaii became the 49th and 50th states in 1959. Old flags are supposed to be burned, and wouldn't have been used for civic events such as ticker-tape parades.

Factual error: While orbiting Venus, Barton receives instant responses to his radio communications with Earth. At that distance, there'd be a considerable transmission delay: at least 1-2 hours.

Revealing: Mismatched stock footage puts the Venus-bound Barton in four different spaceships during his journey. We see brief shots of a Vanguard rocket launch, an Atlas missile, a V-2 rocket sequence, and finally, special effects shots of the ship borrowed from the 1950s SF series "Men Into Space." Not one of these vehicles even remotely resembles any of the others.

Continuity: When Dr. Stone's assistant helps him up from the floor, there's a lopsided, circular diagram drawn on the chalkboard behind them. One shot later, the diagram has changed into a perfectly round circle and has moved itself several inches higher on the board.

Plot hole: Eck gives Dr. Stone one of his eyes so the scientist can create a lens to improve the alien's vision. At the end, Stone hands Eck the lens, but not the eye. When Eck puts on the lens, his missing eye reappears out of nowhere.

Continuity: Eck tears a leaf from Stone's notebook. But the close-up insert of the page and the following shot of it being torn out reveal two completely different sheets of paper. The first has only a brief list of four names and addresses. The second is covered with handwritten notes. They don't match, yet they're supposed to be the same page.

Factual error: Someone in the set decorating department must have failed first-year Spanish. The name of the apartment complex (Spanish for "The Flowers") is prominently displayed over the archway, but has both words misspelled, reading "Los Floras." It should be "Las Flores."

Visible crew/equipment: After Roy forces Peter to drink the formula, the boom shadow makes a very intrusive appearance on the wall above them.

Continuity: Andy's car crashes into a boulder in the beginning and stalls. But when he gets the engine started and drives away at the end, there's no damage at all to the front end of the car.

Visible crew/equipment: A glass shield used to protect the camera from a styrofoam rock slide shows us the ghostly reflections of several film crew members, including one wearing an enormous "10-gallon" cowboy hat.

Continuity: From the Mars rocket's cockpit, Boomer hears Thomas scream once, shouts, "I'm coming!" and races out. When Earth Command hears this on delayed radio transmission 3.5 minutes later (it would take much longer than that from Mars, by the way), there's added dialogue, and this time Boomer never says "I'm coming." We also hear Thomas scream twice instead of just once.

Deliberate "mistake": Though by 1964 it was already suspected (and later confirmed by Mariner IV) that Mars has an atmosphere humans can't breathe and temperatures too low for humans to tolerate, Merritt and his crew are here exploring the planet sans spacesuits. This was "fudged" because space helmets A)are expensive, B)reflect cameras, and most importantly, C)obscure the actors' faces.

Visible crew/equipment: During Ellis and Cutler's conversation in the courthouse foyer, the boom shadow makes two appearances: once over Ellis' shoulder when they start across the hall, and again over the elevator doors.

Visible crew/equipment: As Hadley stands near the lockers, talking to Larkin and packing, the boom shadow dips into the shot over his head.

Visible crew/equipment: When the black Ford pulls up to Minns' apartment building and Ballard gets out, several studio lights and reflectors are mirrored in the car's shiny surface.

Continuity: Ballard reports that 6 bullets were fired at Minns. He's a trained investigator, but he apparently can't count as well as the viewers can. We saw his men fire at Minns - 7 times.

Visible crew/equipment: When Minns pulls up to get Johnny, the entire camera crew and several lights are reflected in the side panels of his station wagon.

Factual error: Outside the warehouse, one of Ballard's men is talking on a car phone. We're not sure who he could connect with, though. The car has no mobile transmission antenna, and in the 60s, it would have needed a very large one.