Throughout the movie, various goaltenders - especially Craig and Tretiak - are shown wearing Tuuk-style blades on their skates. Tuuks for goalie skates were not developed until the mid- to late-80s. In the era of kick saves, plastic blade holders were thought to be too risky for goalie skates.
At the stands selling merchandise to support the participating countries before they start, there's a man selling at a stand wearing a white cowboy hat with three pins of three different countries' flags on it. One of those flags is the Russian flag of the Czars and the Federation, which was not used during the Soviet era.
On the back of his shirt, the player typically called "Kharlamov" in the west, has his name spelled as "Charlamov", which is correct. Sometimes the announcers would pronounce his name "Harlamov". In Russian, when a kh comes at the beginning of a word, it is pronounced like an h. If spelled with "ch" it would be pronounced as "Sharlamov", which almost no one (in the movie or real life) got correct. The "C" in the Russian alphabet is analogous to "S" in the Roman alphabet.
When cutting players from the team, one shot shows the name Les Auge crossed off while Craig Patrick crosses off the name Jack Hughes. A short time later another shot shows him crossing off Auge with the name Hughes unmarked.
When Jack O'Callahan checks Krutov into the boards just before the U.S. scores their first goal against the Soviets, he is shown to come to a stop lying against the board. In the next shot where he is shown lying down watching the goal scoring play develop, he is lying a good ten feet or so from the boards.
When Walter Bush announces pairings for the medal round at the press conference, he gives the US vs. Soviet game face-off time as 17:00 hours
(or 5 pm). Before the Soviet game in his office, after Herb Brooks is finished reviewing his notebook and checks the lineup card, he looks at his watch. The time reads 7:20 p.m., which is 19:20 hours, several hours past the previously announced 17:00 start time.
The US Flag is shown draped over Jim Craig's shoulders with the star field downward (upside down), then there is a brief cutaway, then when the camera cuts back, the flag is now star-field-up(right side up). There was no time for him to have changed it himself.
When the team skates its "Herbies" after the Norwegian game William "Buzz" Schneider is shown participating in the drill. In real life he was thrown out of the game for fighting and did not dress to skate after the game with the rest of the team.
In the game against Sweden when goalie Jim Craig is pulled for the sixth attacker, Mark Johnson is shown being sent in as the extra attacker. In the actual game, Dave Silk was the extra attacker sent in.
Although U of Minnesota did beat Boston U in the 1976 NCAA playoffs, Rob McClanahan was still in high school that year. He played for The U and Coach
Herb Brooks 1977-79. In the movie, O'Callahan tells story that he had been "cheap-shotted" by Mac in '76. Couldn't have happened.
In the 2nd period on the third Soviet goal by Maltsev, the player is scene crashing into Jim Craig. There was no collision on the play, only a clean goal on a break away. There was a collision on an unrelated play during the 2nd period.
Before the U.S.A. scores its third goal in the match vs. the U.S.S.R., Al Michaels says: "PETROV going off for slashing". And they show us a player with number 16 on the shirt. And the announcer confirms: "Soviet Union penalty to number sixteen, PETROV". Later on the scoreboard indicates, that 17 seconds are left in the penalty for the player number 16 (i.e. PETROV). But when the Americans finally tie the score Al Michaels comments: "So the Americans, just as the penalty to KRUTOV was about to expire, score to tie the game". In the real game that was indeed KRUTOV, who was penalized.
While the team was waiting out a delay at the airport, the highlights of the Soviets' blowout of the NHL all stars are being shown on a TV. This game was the third game of a series that took place in February, 1979, before the Olympic team was chosen.
After the Czechoslovakia game Brooks is seen walking with Walter Bush talking about all the media attention the team is getting. He tells him that they have only won two games. This is incorrect. They have played two games, However, at that point in the film they have only won one game, the one against the Czechs. The first game they played against Sweden ended in a 1-1 tie.
After the USA takes the lead 4-3 with 10 minutes to play, the movie depicts 12 shots on goal against Craig just during those final 10 minutes. In real life, the USSR only had 9 shots on goal for the entire 3rd period.
Right before the Soviets score the first goal of the game, Schneider is slashed by Krutov, falls down on the ice and loses control of the puck to a Soviet player. In the real game, however, there is no slash on the play, only a simple stick check by Krutov which is permitted in ice hockey, and Schneider doesn't fall either.
When Vladimir Myshkin replaces Vladislav Tretiak to start the second period, Al Michaels and Ken Dryden discuss the rarity of Tretiak being put on the bench, and that it had not yet happened during the 1980 Olympics. In fact, Myshkin had played the entirety of USSR's group stage games against Netherlands and Poland, and replaced Tretiak after one period in USSR's game against Japan. These appearances by Myshkin, however, were due to USSR's ease in winning against much weaker opponents; it is true this was the first time Tretiak was replaced for poor performance.
On Mike Eruzione's game-winning goal, the film shows Eruzione taking a pass from the offensive zone while outside of the blue line, then skating inside the blue line and firing the game-winning shot. Had the play actually occurred in this manner, the play would have been whistled dead for an offsides. Eruzione's goal, in actuality, did not occur as depicted and took place with no infraction.
During the match against West Germany, the scoreboard shows that the U.S. is playing the GDR, the English abbreviation for East Germany. The score board in the original game was incorrect - the scoreboard coordinator in the original game made the mistake, not the filmmakers.
The audio of President Jimmy Carter's (presumably) live address is heard during the Christmas scenes of the movie. This famous "crisis of confidence" speech was actually given on 15 July 1979, nowhere near the Christmas season. However, if you listen to the entire radio commentary, it is a "Year in Review" radio program, which would make the playing at Christmas-time accurate.
The hockey competition was NOT a single elimination (knockout) tournament. In the first round, twelve teams were divided into two groups. The top two teams from each group advanced to the medal round and were awarded points based on their result against the other medal round-qualifiers from their group. USSR were seeded first with two points, by virtue of their preliminary round victory over Finland. USA and Sweden tied at the beginning of the competition and had one point each in the initial medal round standings. USA beat USSR and Finland to finish first with a total of five points, USSR beat Sweden in the final game of the competition to finish with four points, Sweden finished third by way of their tie against Finland, which finished fourth with one point.
In the very beginning of the movie, the voice-over newscast is talking about the 26th Amendment to the Constitution, which lowered the voting age to 18. The commentator remarks that the president indicated that he would sign the amendment into law. While constitutional amendments do not require the president's signature to become law (simply a vote of Congress and ratification by three-fourths of the states), presidents can sign amendments after passage by Congress--and Richard Nixon did so for the 26th Amendment, at a ceremony in the East Room of the White House on July 5, 1971.
At the end of the second period when Johnson scores the goal it doesn't actually go in the net. It visibly passed behind the net from the left side and the puck can clearly be heard hitting the boards.