While riding in a limousine, Joanna's hairdo is first shown with bangs, then without bangs, and then with bangs again.
When Mark and Joanna are riding away in the concrete pipe, it can clearly be seen that the truck carrying them has a large set of wheels as the furthest back portion of the truck, which would make it difficult for them to just jump out. When they are jumping out, the large set of wheels is gone.
At 1:26 into the movie when Audrey Hepburn goes to kiss Albert Finney overlooking the ocean, the film isn't cut properly so that Hepburn doesn't start at the proper frame; she just runs in from the middle of the camera.