When Taylor looks back at the ship's clock for Earth in Planet of the Apes (1968), it reads November 25, 3978. However, Brent tells his dying commander that the year is 3955. This is repeated in Escape from the Planet of the Apes (1971), displayed within Taylor's ship.
When the Apes are faced with visions of fire, a statue of their Lawgiver bleeding, and their eleven missing soldiers being crucified, Dr. Zaius urges Ursus to shoot the suffering captives. Ursus resists, stating that the Lawgiver has forbidden Ape to kill one another. However, later on in the first film, Zaius warned Cornelius and Zira they could hang for high treason.
When Brent and Nova are running along the hillside after the horse is shot, his arm bandage clearly falls off, but in the next shot which is closer, it's back on again.
As the apes break into the cathedral, Mendez is wearing his purple sash before they enter. After the apes make their way in, it's disappeared.
(at around 57 mins) When Brent first encounters a mutant, Verger, he can see the "alpha omega fins" of the doomsday bomb. He turns and runs back to the double doors (2 seconds), turns around to respond to Verger's "beeps", and in this impossibly short time the bomb has already been lowered into the silo, so only the top is visible.
(at around 42 mins) When Brent is in the subway station, on the wall it says that it's "Queensboro Plaza". Queensboro Plaza is not an underground station. It is an elevated station.
When Brent enters the subway, he discovers a public phone mostly encased in rock. The 2,000 years between the present the time of the apes is nowhere near enough for rock formations to form, which would require millions of years. (Note: the phone booth had become encased in molten masonry, resulting from the city being inundated by thermonuclear explosions).
In the first movie it was established that the apes (while obviously speaking English) have developed their own hieroglyphs and alphabet. The patches on the clothes of the chimps is one example for their usage.
In "Beneath" however, the chimps suddenly use normal English words on their protest signs ("Wage Peace Not War") instead of their hieroglyphs.
There is no way Brent could have survived a crash landing as depicted without at least getting seriously injured.
Rock formations have buried New York, which is something that would take millions of years to occur instead of just 2,000 shown. On the other hand, if New York was buried by lava that later hardened into solid rock, there is no way there would be spacious caves for Brent and Nova to walk through as caves take millions of years to form by running water. All of the buildings they pass would have been completely destroyed long ago as well.
When Brent changes clothes behind the bush, he is wearing boxers. After the horse is shot and he falls along the hillside, he is obviously wearing briefs. Brent actually removes his boxers before putting on his animal skin loincloth.
Taylor and Nova (and likely many apes as well) would have heard and seen Brent's spacecraft as it flew over and crashed. However, Taylor's ship came down unnoticed so it's more than likely Brent's did as well.
Deep in the Forbidden Zone, Dr. Zaius and the gorillas come across one of the air vents leading to the underground ruins, obviously built by the survivors of the ancient holocaust. However, instead of a round opening (as we had seen in the background when Brent and Nova were traveling within the vent system), we're shown the same rough cave entrance that Brent and Nova had entered at the perimeter of the Forbidden Zone. This isn't the same entrance Brent and Nova entered. They entered a cave by the perimeter of the Forbidden Zone whereas the apes entered through one deeper in the Forbidden Zone.
(at around 22 mins) When Brent is shot in the arm by a gorilla patrolman, a bird is seen flying away. Yet in the first Planet of the Apes (1968) movie, Cornelius and Zira argue with Taylor that flight is a scientific impossibility and Taylor makes a paper airplane to prove his point. Zira may have been referring to mechanical flight.
(at around 22 mins) In the "steam room" scene, Zaius and Ursus are wearing only towels, yet they seem to have twice as much body mass naked than when they are wearing their costumes.
Obvious pull-over ape masks (e.g. empty eye sockets) on the apes during Ursus' speech to The Ape Council.
(at around 20 mins) During Ursus' speech to the Ape Council, James Gregory is very animated. He is so animated, in fact, that near the end of the speech he turns and lifts his head, revealing his throat and Adam's apple.
(at around 42 mins) When Brent finds the pay telephone in the subway he hits the stone wall and it gives, revealing it is only foam.
(at around 11 mins) At the beginning of the film, where Brent meets Nova for the first time, 2 taped position markings (bright white letter T's) can clearly be seen on the ground behind Brent. These markers appear and disappear between shots.
It was not made clear what was producing so much light within the underground ruins.
Ursus is seemingly killed after being shot once by Brent in the torso. Considering he was wearing armour, it should have taken more than just one shot to eliminate him. (Note: Ursus and his subordinates were not wearing armor, just their usual leather uniforms).
A walk from Queensboro Plaza Station past the New York Public Library, New York Stock Exchange, Radio City Music Hall, and ending at St. Patrick's Cathedral is 11.1 miles over land on New York streets. Unless all these landmarks had been lifted up and deposited all together, it would be a very long and difficult journey for Brent and Nova underground, on gravel and dirt surfaces, in bare feet.
The underground telepathic mutants claim to be a "peaceful people" but the idea of "get[ting] [their] enemies to kill each other" as well as inflicting deterrents on who they consider enemies contradicts such a statement.
When Taylor and Nova are riding through the lightning, in one shot there are tire marks on the right side of the frame.
Virden and Burke (from the TV series) find a book in the library with a photo of New York City dated 2503. So it's clear that mankind existed at least up to that point in time. Therefore it makes little sense that a 1970's style rotary telephone and a 1970's city bus would exist in 2503 or later. (Note: Evidently, Galen's world existed in an alternate time-line).
Brent says to the mutant tribunal he was in Ape City "two days ago." The time line of the movie doesn't appear to imply that such amount of time between Brent setting foot in Ape City and ending up in the underground city had passed, unless he and Nova spent that up to that long hiding in the Subway ruins. (Note: This film's script went through many revisions. Evidently, one or more of the earlier ones had taken Brent and Nova two days to reach the underground ruins, but this particular line hadn't been adjusted in the final shooting script).
At least one of the Ape soldiers has blue eyes as shown in several shots. Needless to say apes only have dark eyes.
(at around 38 mins) When Brent tries to get the reins from the runaway horses you can see an extra set of reins going into the paddy wagon through the holes in the wall, to a hidden driver. After Brent stops and dismounts, the reins disappear.
When Brent fights the gorilla on top of the jail transport cart, the gorilla stands on his neck, but is knocked off the cart by a tree branch. He then lands on some hay. The cable pulling him backwards and onto the hay is visible.
(at around 16 mins) As Brent and Nova start to ride away from the wrecked spaceship, a white paper cup blows from the camera position. It blows along the ground into the center of the frame and then around behind the horse.
This film and Planet of the Apes (1968) turn out to take place in and around the ruins of New York City but the geography is of deserts, forests, mesas and plateaus. New York and its surrounding area is totally urban in real life and even in the event of nuclear war, the geography would not altered, especially in a period of 2 thousand years.
Taylor gives his dog tags to Nova. In Planet of the Apes (1968), he does not have dog tags when he is captured by the apes, or when he rides off at the end of the film. There is nowhere he would have gotten them since his ship sank and his supplies and clothes were destroyed by the indigenous humans. Even if he had somehow brought his dog tags along, they would have been confiscated by the ape council at his "trial". (Note: Taylor was originally captured wearing the remnants of his uniform, in which Taylor could've placed his dog tags within, having recovered them among their trail of stolen possessions, then Zira finding them sometime later, returning them to Taylor off-camera before they arrived at the seaside cave).
Brent was sent on a rescue mission to look for Taylor and his crew. This makes absolutely no sense for myriad reasons, including:
1) The first Planet of the Apes (1968) film specifically states that the crew was traveling near the speed of light. As such, decades or even centuries must have passed on Earth. Since the scientists who sent them on the mission would know, why would they send a rescue for a someone who they would never live long to "miss?" (the only way it would make sense is if Brent and his Skipper had been following Taylor's ship at a distance in case they needed assistance, and just never mentioned on the first film).
2) Where would they have "looked" for Taylor's mission? Space is a vast place and even sending a ship along the same route as Taylor would be no guarantee that they would ever find his vessel.
3) Even if Brent left the day after Taylor did, it would likely be decades or centuries before he caught up to Taylor, in which case the people who sent them both would be long dead before they knew if either mission was successful.
There was no need to sent Brent on a "rescue" or recovery mission as it would have taken place decades or centuries later than it would possible or necessary.
There was no need to sent Brent on a "rescue" or recovery mission as it would have taken place decades or centuries later than it would possible or necessary.
Taylor's narration at the beginning of the first film as well as his conversations with his crew mates make it clear and obvious they never plan to return to Earth (or rather Earth's past). So it's unknown/clear why Brent was sent to rescue Taylor and his crew.
Although Cornelius and Zira were indicted for heresy in Planet of the Apes (1968), there is no mention of this fact in the film. Since the events of the first film, they have gone from being enemies of Dr. Zaius to trusted colleagues without explanation. (Note: After destroying the cave on the first movie, Zaius may have had a change of heart and pardoned the couple in exchange for the promise of keeping their knowledge of their true history a secret from the ape population, then making them members of the ape's scientific council where Cornelius would've had access to secret scrolls he would mention on the next film, which told the story of the apes' slavery and subsequent uprising).
Just before Taylor disappears in the Forbidden Zone shortly into the film, he tells Nova to "try to find Zira." Why send her back to Ape City in an attempt to look for Zira? She could risk being recaptured by the apes, or even worse, exterminated. Not to mention they've pretty much become fugitives. Taylor should also know, based on what he went through during Planet of the Apes (1968), that this isn't a good idea. (Note: Taylor was confident that if Nova ended up recaptured, Zira would take care of her, which would be preferable to dying in the Forbidden Zone).
When Brent and Nova come across the first fountain of water with dirty-looking water in the underground ruins, Brent immediately spits it out after trying to drink it. Its dirty and murky appearance should have been a strong indication it was not safe or ideal for drinking.
When Dr. Zaius is visiting Cornelius and Zira, he refers to them as "You two psychologists". Cornelius is an archaeologist, not a psychologist.
Brent states to the mutant tribunal that Nova helped him break out of Ape City. Zira actually helped the two escape. (Note: Nova had led Brent to Cornelius and Zira, who helped them escape the city).
Cornelius and Zira mistake Brent for Taylor. However, the fact that he was wearing part of a white spacesuit, had blonde hair and a beard and was a bit shorter, unlike Taylor when he last seen, should have made it obvious it was not him. (Note: Zira was aware that it wasn't Taylor; her reaction resulted from her surprise of encountering a human resembling the look of Taylor, who she had previously regarded as unique).
Later in the film, Brent tells Taylor about the bomb the mutants worship. Taylor asks what type of bomb it is, an obvious indication he's never seen it. Once Brent says it has the Greek letters "Alpha" and "Omega", Taylor realizes that it's a doomsday bomb. (Note: Taylor was unfamiliar with the bomb, but he was familiar with the phrase "Alpha and Omega", which translates to "The beginning of the end").