Umpires are shown wearing the micro mesh pullover style shirt in the movie's recreated games, a uniform that did not exist in 1990-91. In one night game sequence, the umpires are wearing the navy blue micro mesh shirt, something that wouldn't have appeared on the high school field until the 2000s. In the actual footage that is used throughout the movies, the umpires are wearing the "proper" powder blue button-up that was worn in the early 90's.
The final game is supposed to take place in 1991 at Veterans Memorial Stadium in Cedar Rapids. However, that ballpark was torn down between the actual game and the filming of the movie. The stadium in the film in the current Veterans Memorial Stadium, which opened in 2002.
During the scene that shows the game when the Norway team is not playing well, just before coach Stock chews them out for not playing heads up baseball, the game is being played on a bright sunny day. In one scene a player is shown slamming his bat to the ground in the dugout but in the background it is clear that the lights are on and it is dark outside and when the scene shifts back to the field, it is bright and sunny again.
In the first inning of the final game Kevin Stewart # 20 was batting 3rd after # 29 strike out. He came up to the plate. But # 30 Mitch Akers took the swings for him. In the 7th after #29 got hit by the pitch # 20 did bat and tied the game with a hit.
In the final game the announcer says Clay goes ahead in the top of the 3rd. After the inning, Clay's pitcher is upset at being being left on base. Stock says to the leadoff hitter the pitcher will hang one and the batter does hit a homerun. Later, the scoreboard shows Norway with a "0" in the 3rd inning.
In the championship game at the beginning of the movie the scoreboard shows Norway on bottom, meaning they are the home team and they would bat last. The scoreboard shows that Norway had scored 1 run in the 6th inning. But, they had not even been to bat in that inning. But the run is moved from the sixth inning to the seventh inning a few moments later so its simply a scoreboard operator error.
The movie shows that Van Scoyoc coaches briefly in the Detroit Tigers farm system. It clearly indicates Niagara Falls as a AAA club, when in fact it was a single-A farm team. Toledo was (and is) the AAA team for Detroit.
When Stock is proving his capacity with the home run challenge, the players are grouped 2/3 of the way down the 3rd base line. This is an extraordinarily dangerous location for them and they would not have stood there in reality.