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: Upon arriving to the house they say Zoe's mother committed suicide when she was 10 but later on before going back to the house to expose her step mom Sam says her mom committed suicide when she was 8. (00:16:56 - 01:17:46)
Character mistake: Hellboy's stone hand is on the wrong side when he's fighting the first giant. (00:32:50)
Character mistake: Toward the end of the film, Detective Davis orders Captain McKenna to put his badge on the table. New York City police always refer to their "shields", not badges.
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 start Smith takes a Krestal ballistic computer and barely holds it out to get wind speed. The proper technique is to hold it at arm's length into the wind.
Character mistake: Nicolas Cage says "first battalion, tenth Marines from Camp Lejeune, North Carolina gunslingers signing out". It was the second Battalion 10th Marines that was called gunslingers, not the first.
Character mistake: Casey is sixth of six male students standing in a row to individually demonstrate a karate move for Sensei. After the fourth student, Sensei passes up student #5 and says, "Next. Casey." Sensei completely missed the fifth student, the only other beginning white belt like Casey. (00:28:45 - 00:29:10)
Character mistake: Shaft meets Junior for the first time and mocks him with the offer of bubbly water. Junior says "And as for that wedge of lime, it makes it alkaline, so..." It wouldn't, since lime juice is rather acidic. (00:23:10)