When the barber applies the shaving cream, some of it ends up below Willie's bottom lip. However, the next time his face is seen, it is no longer there.
The ticket from River Junction to Boston given by Bill Sr. to Bill Jr. changes in two close up shots.
After the tools fall out of the bread, the intertitle reads "must of" instead of "must have".
During the final cyclone sequence, a cable pulling down the entire front of a building is visible.
Steamboat Bill only notices that the man bending over is black after he has walked to behind him, and the man stands up straight. However, Bill kept looking at the man as he was walking around him and would, therefor,e already have seen the right side of his face.
When a small table tilts to its left, the head of the doll on top of it rotates towards its left as well, presumably as a result of the friction with the back wall. However, in that instance the doll's head would actually have turned the other way.
Just before the house facade falls on Bill, Jr., a stagehand can be seen through the first floor window giving it an extra push.
When Bill Jr. enters the jail and the sheriff closes the door, the hand of a crew member can be seen outside reaching for the door.