Continuity
In the supermarket scene the items on the shelves are moved from Martha walking past to when Francis walks past.
After Von kicks Martha to the chest into the wall blood is clearly seen covering her teeth. Once the tape is removed later her teeth are clean again.
About 44:50 when Martha demands to be taken home after seeing Francis kill someone the Corvettes roof is up. When they arrive home the roof is down.
Martha and Sophie's wounds from the cat attack vanish by the next day...
Errors in geography
The final scene takes place in North Vietnam. There is no longer a North Vietnam, not since the end of the Vietnam war.
Revealing mistakes
After the closing shootout, it is raining heavily, but the sky in the background is clear blue and the trees and church across the street have sunlight on them. When Francis and Martha descend the stairs, they also have sunlight on them. Thus, the rain is revealed as fake.