Revealing mistakes: During the song "That's all I'm askin' for", when the guys are standing in the ling with their arms dancing back in forth, right before it goes to the next shot, you can see Trey Parker (Alfred Packer) mouth the words "cut" to end shooting.
Continuity: Packer shoots Bell with a single-action black powder pistol, yet he does not cock the gun, and the hammer does not move when firing. At the same time, there is an audible cocking noise.
Crew or equipment visible: When Alfred Packer is running from the crowd from the bar, there is a clear, visible line in the sand where he is supposed to run.
Continuity: Right before Packer and the others meet the trappers for the first time, you can clearly see that Leanne is tied up. She is also clearly tied up during the "All We're Asking For" song. Right after she ran away, Noon asks Packer if she was tied up and Packer replies that he never ties her up.
Errors made by characters (possibly deliberate errors by the filmmakers): Frenchy Cabazon states that his song about life as a trapper is in F sharp major. The song is actually sung in F minor, with one section in G sharp minor.
Errors made by characters (possibly deliberate errors by the filmmakers): When the men are naked under their blankets and Humphrey remembers the fudge it is sitting just under the blanket on his stomach so the sudden realization of the fudge's existence is forced. The fudge would have to have been taken from his pack and placed there after undressing and laying down and if the characters are so starving it is unlikely he would have waited so long to break into it.