Character mistake: During the debrief meeting with the generals, Roy states the Lima Project was "some 29 years ago" and "the ship disappeared approximately 16 years into the mission." A few minutes later, Roy narrates "I was 16 when he left, 29 when he disappeared." This of course is only 13 years into the mission. (00:11:27 - 00:15:03)
Character mistake: Some characters use the letter "s" at the end of a Pokémon's name when the plural of a Pokémon is just its name. The best example is when Pikachu says, "Roger must've sent the Greninjas to cause the car crash." Being a Pokémon himself, there's no way Pikachu, out of all characters, would say that.
Character mistake: It's merely training, but her opponents are hostile and want to exclude her from playing, so it's funny then that they don't call Kim out for her actions being egregious fouls; she brings the ball trapping it between her feet in multiple cartwheels (you can't just hold the ball between your feet for prolonged amount of times and 'carry' it). You could also say she kicks the ball at an opponent's face on purpose, which is equally unsporting. (00:24:00)
Character mistake: In her first walk through the city with Dr. Ido, after feeding the dog her sandwich, Alita takes a flyer and reads it. Between the lines that read "Wanted" and "Murder" there is a line in Spanish that says "Querido para el asesinato." It should say "Querido por el asesinato".
Character mistake: Hellboy's stone hand is on the wrong side when he's fighting the first giant. (00:32:50)
Character mistake: When they infiltrate the military facility, Steve and Tony are trying to blend in. Steve wears his hat the entire time he's indoors. He's a soldier, taking his hat off when he comes through the door would be second nature to him. Not removing it would make him stand out as someone who doesn't belong - Steve knows better than that.
Character mistake: Right at the beginning of the movie, introductory technobabble. "In this canister, there's a solution of protons. The canister is attached to a rotor circuit that generates the protons to the speed of light." I believe the science genius and creator of time travel mixed up the words "generate" and "accelerate" here. (00:00:50)
Character mistake: At the skate park, Thor said he wasn't into girls because "girls are a distraction." Thor was interested in going to Soren's party because a lot of the popular boys were going to be there. When the "spin the bottle" landed on Thor, he said he couldn't kiss Brixlee and went upstairs. Hannah and Lily came home and told Thor it was OK that he wasn't ready for a kissing party and still had a lot of time before becoming interested in girls. Max previously told Thor that he wasn't as mature (sexually developed or undergoing puberty). Therefore, Thor's statement in the cafeteria about his new earring - that he "wasn't going for cute", he was going for "sexy and hot" - was incongruent and incompatible with his character.