Continuity mistake: Adding to Kelly Leak's homerun in his first at bat shown in the movie (great scene with the ball hit during practice and clears the fence during a game), the celebration at home plate does appear to indicate a game winning homerun (a walk-off no less). However, as the ball clears the fence you can see the score is 0-0 in the top of the third. (00:57:52)
Suggested correction: It was probably just excitement that someone on the team finally hit a home run. This was a bumbling team (remember their first game they didn't get a chance to even bat) and were lacking hits and runs until now. Most likely a confidence booster for the team.
Continuity mistake: In the last inning of the championship game, Buttermaker opens a beer in a short brown bottle (perhaps a Pabst Blue Ribbon, Red White and Blue, or Red Stripe) right before Amanda grounds out. When he exits the dugout following the at-bat, he's holding a Coors.
Continuity mistake: In Kelly Leak's first shown at-bat, he hit a home run to win the game, and the team the Bears defeated was sponsored by Denny's, as you can see from their catcher's logo when Kelly crosses the plate. Problem is, Denny's sponsors the Yankees, who went the entire season undefeated. We know this because in several scenes, including the one after the home-run where the head lady mocked the Bears' victory, you saw the standings where the Yankees had no losses.
Continuity mistake: In the Bears' second to last game against the Athletics, an announcement is made early in the game that the Bears are winning 1-0. But later in the game when you see the scoreboard, it shows the Athletics scored the first run of the game in the top of the second inning.
Continuity mistake: In the last inning of the final game, you saw the Yankee catcher making fun of Ogilve, and it was clear he had blond hair. But in the final at-bat where Kelly tried for a grand-slam but was tagged out by the same catcher, he had brown hair.
Continuity mistake: When Buttermaker puts Amanda's arm in the icy water, he is seen taking out a beer. When the camera changes there are no beers on the bench and he then starts taking them out. Also as he removes beers, the water level goes down in the bucket. After they are removed, the water level is up near the top.
Continuity mistake: In the championship game - last at-bat, Kelly hits the ball to right field. They show the outfielders throwing the ball in from the fence with the scoreboard showing Yankees scoring 3 in the 6th inning and a total of 6, with no run total for the Bears. The camera angle switches to Kelly rounding third and then back to the outfield again. Now the scoreboard shows Yankees total 7 runs and Bears 3.
Continuity mistake: It appears that the first kid over to Joey Turner to get the ball during Engelberg's infield home run is Billy the replacement pitcher, moments later we see that he is on the bench and not in the game.
Continuity mistake: The shadows change dramatically throughout the games (especially the championship game). Shot all different times of day at random.
Continuity mistake: In the championship game, when Buttermaker pulls Amanda off the mound and calls in Stein, He sends Amanda to left field. However, the very next hit is hit to Lupus, and you see Kelly Leak run over from left field to field the ball. Also, when Lupus makes the catch a bit later, you see Ahmad run over from left field to congratulate him.