In the video, you see Pac-man being chased by a ghost. In the first part of the video, the maze scrolls so that Pac-man stays in the center of the screen (side-scroller perspective). In the second part, the maze stays put and Pac-man moves around (static perspective). Both perspectives offer perfectly acceptable gameplay. But the difference in your ability to detect changes is dramatic!
Music: Binärpilot - Robot Wards