Continuity mistake: During the big battle against the Chitauri, Captain America is zapped with a blaster bolt. When Thor helps him to his feet we can see a significant amount of damage done to his suit, just below the star on the right hand side. But later on after Iron Man destroys the Chitauri ship with the nuke, the damage is completely gone. (01:59:25 - 02:02:40)
Continuity mistake: After Stark is paralysed and slightly recovers, he goes to get his energy. Right then the blood around his left ear has vanished. Being seconds away from dying, the last thing he would think of is taking a shower.
Continuity mistake: When Ivan is first brought to meet Hammer, Hammer is eating a dessert with a cherry on it. The cherry disappears and then reappears. The spoon also keeps swapping between being inside the food and by the saucer. (00:45:45)
Visible crew/equipment: After Doctor Strange experiments with the magical doorway in the Sanctum Sanctorum, he leaves it on a desert view and we cut to a shot panning across all the artifacts. At the very start of the shot on the right hand side of the screen is a crewmember standing in the shadows looking bored. Really blatant if you turn up the brightness, but easy enough to spot if you know what you're looking at. (00:56:00)
Continuity mistake: When Doctor Strange attempts to use the Time Stone on Ebony Maw, Maw ties up Strange telepathically and strangles him unconscious. Beside Strange is a police car and a motorbike tipped on its side. Maw then lifts the ground he is lying on, but the police car has been replaced by an SUV and the motorbike has disappeared. The shadows also change. (00:23:25)
Revealing mistake: During the airport scene, after Tony tells Wanda that she hurt Vision's feelings, Tony and Hawkeye have their own banter moment. Then, when Hawkeye says, "Made you look," the next shot as the car is falling, Hawkeye is reversed; note his arm guard. (01:32:15)
Continuity mistake: After Peter gets the text from Happy about meeting at the bathroom, Michelle asks, "What are you hiding, Peter?" and just as she says, "I'm just kidding I don't care," Peter's holding his cell phone up in his left hand, but next shot he's holding the cell phone up in his right hand.
Continuity mistake: When the Destroyer arrives amidst the Shield agents, a coffee cup sitting on the dash of one of the vehicles spills over. The next shot it can be seen lying on its side. The reverse angle shot then shows it upright again. (01:21:20)
Continuity mistake: When Tony is in his garage injecting his arm, his chest piece is glowing brightly through his shirt, however, the very next shot when he is wiping his arm with the alcohol pad, his chest piece is suddenly turned off. (00:05:15)
Continuity mistake: In the scene where Thor tells Jane to hold on, she's on Thor's right side and Mjölnir (the hammer) is in his left hand. As they are traveling through the Bifröst to Asgard, the position of each has changed. (00:28:20)
Factual error: The location in DC has latitude and longitude both as N/S - longitude is an east/west factor. (00:13:05)
Factual error: During the mid-credits scene T'Challa is addressing the United Nations about Wakanda's true nature. A Welsh flag can be seen among the other nation's flags, which would suggest that Wales is a separate nation from The United Kingdom - not the case.
Continuity mistake: Vers KOs the Skrull she does the warcry thing at, and then another one on the corridor steps. She is then seen fighting from the perspective of the corridor to her right, but there are no Skrulls in sight against that door, while at least one was already lying down there. There are two when the camera gets back closer, and when she neutralizes the last one who bounces onto his own stun mace, there are again two, and she somehow got between the last one and the others. (00:20:30)
Continuity mistake: In the motel room, Betty gives Bruce a new heart monitor watch, still in its box. In a subsequent shot, the box has disappeared and Bruce is putting the watch on. The cut to Betty and back is too fast for him to have taken the watch out and junked the box. (01:04:10)
Continuity mistake: SPOILER - The wounds on Pietro's body change. The most noticeable one is on his right shoulder. The amount of blood decreases too.
Continuity mistake: When Quill and Gamora first meet and get into a fight, Gamora grabs the Orb Quill is carrying and runs. Quill throws a sort of laser-based "lasso device" that snares her legs and causes her to fall. She pulls it off, and immediately in the next shot, it's vanished from the ground between cuts. It also had mechanical components, so even if the laser vanished, the mechanical pieces should still be on the ground.
Continuity mistake: Scott grabs the Greatest Grandma trophy from its stem. Shot changes and he is grabbing the rear side. This swaps back and forth.
Continuity mistake: When Steve starts fighting 2012 Steve, he places the case containing Loki's sceptre on the ground. He then starts to run towards 2012 Steve, leaving the case far behind him. The two then start fighting hand to hand, and the case is suddenly right beside them. (01:22:30)
Continuity mistake: When Scott wakes up after falling off Anthony, we can see the floor around the bed and there are no ants there. He then looks down and sees the bed is surrounded by ants.
Continuity mistake: Scott hugs his daughter and caresses her face while she holds his wrist. From the opposite angle, her hand is gone.