The Football Is My Best Friend - S1-E4
Other mistake: Tsubasa is quicker and much more skilled than his friends with the ball and took off much earlier too, but they reach the crosswalk at the same time. (00:04:10)
The Football Is My Best Friend - S1-E4
Other mistake: When Roberto tells everyone that they should try to treat the ball like their friend (except when they kick it, arguably) one of the kids who react with puzzlement at this unusual statement is Tsubasa, but he is the one character who already does that ordinarily as established in previous episodes. (00:02:40)
Other mistake: Tsubasa is talking to 'his friend' the football as he does keepie-uppies. He is normally animated pretty decently during that activity, except in the shot when he is telling his friend about Genzo's skills; he is keeping his torso completely immobile, moving just his thighs, which is just physically impossible. A few shots later his torso is still again but at least his thighs are not in frame (the ball is though, what could he possibly be using to juggle it up?). (00:06:10)
Other mistake: The international dubs (Spanish, Italian, from what I understand even Arabian) have the narrator say that Fujisawa (which is where the international dubs set the story instead of the fictional town of Nankatsu) is renowned for its football teams, plural. That's not true, since the only strong team is Genzo's Shutetsu, and the competing team in the local derby loses 10-0 to them, and the prestige the city has comes from their victory in the previous championship tournament.
Other mistake: Star keeper Genzo Wakabayashi has a trademark hat with his name and a cool logo. According to his manga character design he was supposed to wear the Adidas logo, but copyright issues arose and the Nankatsu logo is a great substitute visually - sadly it makes no sense, because he is sporting it already at the beginning of the anime and the team with that logo will be properly formed only later in the series.
Other mistake: After his ankle injury from the previous episode, Ryo writhes in pain touching...his knee. (00:03:00)
Other mistake: The linesman's flag as he hands the ball to Taki is unreasonably tiny. (00:18:45)
Other mistake: Masaru falls into the river and Tsubasa follows him getting knee-deep and with socks and shoes on, but the moment they step out of the water both are perfectly dry and have no problem or discomfort at all. (00:07:20)
Other mistake: In the Italian dub, Ryo ("Bruce Harper" as he is known in international versions)'s mom yells at him for running away with the football...but Ryo is not carrying any ball. (00:05:05)
The Football Is My Best Friend - S1-E4
Other mistake: In the opening shot of the dinner scene, Tsubasa's soccer ball is on the chair next to him and as logic dictates it is below table level. Later though it is much higher. Conversely, Roberto's head in other shots is so low that looks like he's sitting on the floor. (00:04:45)
Other mistake: Needless to say, having a football on your belly can't cushion the impact with a truck. Even forgiving this obviously cartoonish impossibility, still the way Tsubasa lands looks all kinds of wrong, with the forward momentum instantly halted as the ball touches the ground again. (00:14:25)
Other mistake: Hyuga comfortably catches with his chest a free kick that for no reason seems to have basically lost any strength and speed between shots. (00:09:30)
Other mistake: If Meiwa scored already 10 goals the previous year (when the championship was won by Shuutetsu) it is hard to explain how nobody from Shuutetsu knew about Hyuga, since they were serious contenders. (00:13:40)
Other mistake: Manabu loses his glasses; Sanae hits him with her flag, but the action is animated incorrectly, and he goes down without the pole connecting. (00:09:10)
The Fight for the Final - S1-E24
Other mistake: The Tachibana twins caught the ball at the end of the previous episode, but ball possession is for Nankatsu at the beginning of this one.
No Victory in Semi Final - S1-E21
Other mistake: When Sawada scores, in the reaction shot on the various team members Kisugi is smiling/laughing instead of being angry/worried, and the player who just lost the ball is in the background. (00:10:15)
The Youth National Championship - S1-E17
Other mistake: The whole team is supposed to be at the opening ceremony, but only 9 players are in the group. Ishizaki in the bathroom, but still there are people missing. (00:12:00)
Other mistake: When Genzo browses the coach notes and figures out instantly what should have been obvious to anyone (the opponent never conceded any goal, that is no small detail!), the way the action of the opponent is shown, both attackers were in offside. (00:11:55)
No Easy Way - S1-E12
Other mistake: During the montage with the victorious march towards the semifinals, a Nankatsu supporter is waving a pure white flag instead of the team one. (00:11:00)
No Easy Way - S1-E12
Other mistake: The perspective when Mr. Ozora tells Tsubasa "I'll let you go to Brazil" is wrong; it looks like he's standing right in front of him, but he's on the bleachers. (00:04:50)