Hmmmm. I think I have a few. I had the original NES and man, that Ninja Turks game was hard to put down. Of course there was also Mario. Then I got the SNES and my life was changed forever. All of those games had me hooked. But the very first game I remember playing obsessively was The Oregon Trail.... man I would pay run after run until I beat it flawlessly. Wipes in those days were much more devastating