When the reverend gets attacked by the mayor, after ripping his arm off, you can see a "lump" on the side of the reverend, revealing his actual arm underneath.
When the gay man's mom has her eyeball popped out, in subsequent shots, her "hole" is just painted black over her eye.
During the opening credits, when we see a few characters passing houses, a car with the camera crew can be seen in the windows.
A fire extinguisher can be seen in the background after a vehicle explodes.
Having Port Gamble as an island suits the plot, but Port Gamble, Washington is not an island but is actually a town on the Kitsap Peninsula.