Continuity mistake: When Navin is at the gas station and is being shot at by the sniper, take a look at the arrangement of the oil cans on the rack beside him. One of the cans in the middle of the rack changes color from pink to purple, and some labels turn, between shots.
Other mistake: Handsome and Charming head out of Snakes End (followed by the newlyweds) and begin their long journey. It then cuts to Cactus Jack before he begins the journey, and at the start of this shot as he places Whiskey's bit, we can see the signpost with three wooden arrow signs and the hillside behind him. This is the same location where Cactus Jack lays trap number seven, named "the tunnel in the hillside," on the next day during the journey; noticeable when Handsome and Charming arrive. (00:28:35 - 00:54:45)
Continuity mistake: When the paper airplane flies into the classroom in the wideshot, there's a guy wearing a striped shirt sitting at the back who vanishes in the next closeup. (00:16:10)
Visible crew/equipment: In the last scene while Brian and the others are singing you can see a tourist walking in the background. (01:30:30)
Visible crew/equipment: In the scene when Kermit confronts Doc Hopper he comes walking out of the bar. If you look at the top of Kermit's legs when he walks out, two pair of hands can be seen moving the legs.