Continuity mistake: None of the games in Goon were played in Manitoba, but every rink has Manitoba Liquor Commission advertising on the boards. In the game played in Quebec the advertising on the boards disappears in the zoomed out camera shots and you can see the MTS Centre logo on the scoreboard.
Continuity mistake: When Doug is suiting up for his first game for the Highlanders, the whole team is putting on their road (white) hockey socks, but after Xavier Laflamme enters the room, the whole team is wearing their purple (home) socks.
Other mistake: During the montage for Ross Rhea, there's a clip on the teleprompter showing Ross fighting multiple members of the other team. In the clip, Ross is shown playing for the St. John's Shamrocks and fighting members of the Québec team, but the score ticker at the top of the screen shows the score "MTL 5 BOS 2", two teams in another league that have nothing to do with the game being played. (01:01:10)gobylo
Continuity mistake: When Doug stops the puck with his face he shoots out a mouthful of blood and his bottom lip is fine. In the next shot his lip is split in half.