While Krystyna is driving the car, a road maintenance machine is visible on the road, but soon after none is visible from the rear window.
Throughout most of the movie, the couple was shown driving a Peugeot 403 sedan. However, when they first got back from sailing, with the young guy no longer present, they were in a Mercedes 190 sedan. It was this way until the very end of the movie, when the couple was once again in the Peugeot.
At the end of the movie when Andrzej and Krystyna are driving away from the harbor, the boats in the background change between shots.
When the young boy is trying to stabilize the Christine by hanging off its side, the railing of the camera boat can be seen in the lower left-hand corner of the screen.
In some shots of the yacht sailing, the wake of the camera boat can be seen.
After Young Boy takes out his knife to offer it to Krystyna to cut the radishes he gave her, he then leans back to play the knife game with his hand. As he leans back, the head of a light-haired fourth person can be seen sticking up from the cabin behind him. This is presumably a crew member, but the person is unidentifiable due to the briefness of the shot and the angle of the person's head.