Hehe.. that's a good one!I remember that well on the Amiga and ST. We used to tape a piece of cardboard to the monitor so you could only see your half of the screen.
Easy solution there. That big TV had to come in a big cardboard box. Keep the box and you have exactly the correct sized piece of cardboard! Sorted!
If you haven't played a classic game in years, it's never too late to start!