Why did they build the entire pinball machine themselves? The portion that "plays itself" is a camera attached to some very basic computer vision techniques that boil down to:
When ball detected in flipper area, flip.
You could attach this to any commercial machine by connecting a relay where the flipper buttons would be.
Because it's a university senior design project - they often pair students with related majors together to work on a project over the course of a semester or two. It's about the interesting engineering of the entire project. They never claimed any one part of it was "novel" but the project as a whole clearly is.
When ball detected in flipper area, flip.
You could attach this to any commercial machine by connecting a relay where the flipper buttons would be.