(at around 1h 20 mins) When Erik first attempts to turn the radio telescope, he bends forward in exhaustion, causing his hair to become a bit messy. In the immediate next shot, his hair is perfectly combed.
(at around 1h 14 mins) When Charles is holding the gun to Erik's head while training, the gun is close to Erik's forehead, but not touching it. In the next shot the gun is touching Erik's forehead, then in the shot after that, it's back to being close, but not touching.
(at around 23 mins) At the cantina, while Erik is drinking his beer at the same time with the two former Nazi officers exchanging deadly looks, the amount of beer in the glass of the officer standing in front of Erik changes when the camera angle changes. Seems like a mistake done during the editing of the scenes.
The U.S. battleship at Cuba changes its hull number intermittently between 61 and 62.
(at around 1h 1 min) Before Shaw and his men attack the CIA HQ, Sean is shown eating an Oreo, but when Hank gets up to close the curtains, his hand is on his knee, with no Oreo visible. When the scene flips from the window back to the four mutants, he has the Oreo in his hand again.
(at around 1h 12 mins) The General in the War Room mistakenly calls upon the mobilization of the 7th Fleet to intercept Soviet ships bound for Cuba. It was the US 2nd Fleet that intercepted the Soviet ships during the Cuban Missile Crisis. The 7th Fleet is and has always been, based in the Pacific (currently stationed out of Yokosuka, Japan).
(at around 1h 8 mins) Spelling/grammar during the Russian translation of Shaw's dialog. It says "Now they have their missles places in Turkey...", which should say "missiles" and "placed". They also, misspell missiles twice more.
There is a scene of a military parade on Red Square in Moscow. The parades there are held on May 9th (a WWII Victory Day). At some years there were parades for an Anniversary of the Socialist Revolution on November 7th. The movie is set immediately prior to the Cuban Missile Crisis, which was in October. Also the snow in Moscow would be very unusual for this time of the year.
During the standoff between Soviet and US warships both side are flying "Jack" flags from the bows - warships do not fly these whilst underway.
When the Soviet and the American fleets fire their missiles toward the island, between the missiles fired by the soviets there is the "S-125M (SA-N-1) SAM" which is a surface to air missile designed to shoot down airplanes and it has no ability to be launched toward land targets.
(at around 59 mins) When Xavier and Erik were confronting Emma Frost in the Soviet Union, some might think that it would have been impossible for Erik to crack Emma's neck with the metal bed frame because diamond is one of the hardest substances known to man. Hardness does not prevent cracking. There are different types of material strengths. Diamond's hardness does not mean that it is invulnerable to all types of stress.
People often say that Mystique shouldn't be about the same age as Charles in this movie because she was much younger than he was in the original trilogy. It is actually explained by Hank (Beast) in this movie that her cells age at half the rate as that of a normal human being.
An SR-71 Blackbird can only hold a maximum crew of 2 in the cockpit. The scene where they are sitting in the back is actually just engines. However, despite their similar appearances, the plane we see the X-Men using here is not a Blackbird, but an early prototype of the "X-Jet" that they use in the films set later.
(at around 34 mins) When the submarine part of the Caspartina separated from the ship part, the ship part would have lost its ballast and water-tightness and immediately sunk on top of the submarine part. However, if the boat was specifically designed for this sort of two-craft partnership (which this pair obviously was), the boat craft would have extra ballast, an 'airlock' system to restore water tightness, and additional fittings to allow it to function. (Craft of this type do exist today, although the submarine components are smaller).
(at around 1h 21 mins) Erik's memory of celebrating Chanukah with his mother includes a seven-branched candelabra. In Jewish tradition, Chanukah is celebrated with an nine-branched candelabra. However, at every other time of the year, Jewish families will frequently use 2, 3 or 7 candles to celebrate the Sabbath every Friday evening.
(at around 3 mins) When the young Raven is in her true form, the seams of her costume are clearly visible.
(at around 1h 11 mins) When Emma Frost cuts the glass of the interrogation room, she taps it towards the outside, yet it clearly falls inside the room.
(at around 55 mins) In the establishing scene outside the secluded Russian manor house an ostensibly Russian military helicopter lands, clearly displaying its UK Civilian Register mark of G-CHOP. The aircraft is a licence built Westland AB-47G.
(at around 40 mins) When Emma is going to get ice, Azazel's tail is clearly missing as he helps pull the sub's ladder down.
(at around 1h 40 mins) When Magneto pulls out the submarine, he uses his right hand to hold on to the Jet and left hand to lift the submarine. But in the subsequent shot when Beast moves the jet towards the beach, Magneto is shown on the other side, with the holding and pulling actions swapped.
(at around 18 mins) In the hotel, when Moira spies on Sebastian Shaw, there's a bowl of M&M's on the table. Some are blue, a color not added to M&M's bags until 1995.
(at around 49 mins) When Erik and Charles are talking on the steps of the Abraham Lincoln Memorial, one can notice the WWII memorial in front of the Washington Memorial. The WWII memorial was not built and open to the public until 2004.
The Film shows CIA headquarters at Langley In 1962. The construction for the Langley headquarters didn't even start until 1965. The first secretaries didn't move into the building until 1968. In 1962 the CIA operated out of several different buildings in D.C.
The Coast Guard cutter in Miami has "US Coast Guard" painted on its hull. Coast Guard cutters didn't add the letters "US" to their hulls until the 1990's. Before that they just said "Coast Guard"
(at around 48 mins) In the submarine, when Emma Frost asks Azazel if there is anything around he replies it is all clear on radar and sonar. A sonar ping is heard in the background with a distinct echo indicating a contact about four to five hundred yards away.
(at around 22 mins) Magneto finds out that Sebastian Shaw is hiding in Argentina, in "Villa Gesell". When the scene takes place there the camera shows a view of mountains and snow. Actually "Villa Gesell" is a town on the beach in Argentina (no mountains there). The image shown on the picture looks like Bariloche, which is in the mountains and has a large German community.
(at around 40 mins) When Shaw's submarine is hiding under the ice and Emma is going up to the surface to get him some ice, you can clearly see a very popular Swedish landmark named Lapporten in the background. This would suggest that they're actually hiding in the nearby lake and not in the sea. It would be very difficult, if not impossible to sneak a submarine into that lake since it's very far from the sea.
(at around 21 mins) In the map of the USSR shown as the General speaks after the Las Vegas scene, Kiev is shown near the border of Poland. It's not; it's hundreds of miles farther east.
(at around 27 mins) When Colonel Hendry meets Sebastian Shaw on his yacht, they are supposed to be in Miami. In one of the wide angle shots, you can see a long suspension bridge in the background. There are no suspension bridges in Miami. It appears to be the bridge near Jekyll Island, GA.
The helicopter that brings Emma Frost has a registration number that starts with G that registration letter is for Great Britain.
In the very first scene when young Erik is pulling open the metal gates, the guards who are restraining him are pulled towards the gate with an equal and opposite reaction. However, that does not seem to be the case when Magneto levitates the submarine. He is raising the sub with one hand and bracing himself against the jet with the other. One would have to suppose that the X-Men jet could hover while lifting the weight of a full-size nuclear submarine.
(at around 1h 8 mins) During the negotiations with the Russian General, Sebastian Shaw points to Iran on the map when actually he is speaking about Turkey.
When Moira stumbles into the secret room at the Hellfire Club, Emma Frost should have immediately detected her presence since there was merely a bookcase separating them. She had sufficient time to detect before morphing into her diamond form.
(at around 26 mins) A quite drunk Charles tells a Moira her auburn hair stems from a "mutated MCR-1 gene". It is actually a mutated MC1R - Melanocortin 1 Receptor - gene.
(at around 15 mins) The scene when Magneto pulls the filling out of the bankers mouth. After removing the filling the man grabs the wrong side of his mouth in pain.
Emma has telepathic powers so she should have been able to feel Moira while she was behind the bookcase before she turned into diamond form.