Continuity mistake: When Tom plays checkers with Bill and makes his last, winning move, there's a cut to a wide angle where the pieces on the board are arranged differently. (00:08:20)
Revealing mistake: After the assembly where Grace speaks to the Dogville people she walks home chained to her wheel. However, the wheel that's supposed to be so heavy that she can hardly move around gets pulled along with the chain hanging through a little. (02:05:10)
Revealing mistake: Before the Thanksgiving dinner the air is full of seeds which are supposed to be carried here from far-away meadows. However, all seeds fall down absolutely vertically like light snow in calm air, and there is no hint of the wind that blew them here. Plus, when the people sit down for dinner the seeds disappear between shots. (01:03:10 - 01:05:40)
Continuity mistake: After Grace has been accepted to stay at Dogville, Tom, the keen observer of the townfolk, takes her around and gives her some background information about all the people who live there. Grace learns that Ben pays a visit to the whorehouse once a month, but later, when he rapes her on the apple truck he tells her that he goes there once a week. (00:24:25 - 01:51:10)