Continuity mistake: Steve props himself against the back of the armored car with his arms folded and legs together stretched outwards to wait for the bad guys to drive up. When they do, Steve is now sitting on the rear bumper of the armored car with his legs spread and his hands on his knees.
Continuity mistake: After Steve rescues Susan from the quicksand, her white pants are wet and covered with dark mud, except a few consecutive scenes later when her pants are spotlessly clean.