My "thing" when I was still gaming was to finish games on Legendary mode (or whatever mode it would be called). Most games had either Easter eggs or unlockable "perfect" endings if you either did that or finished a game without losing a life (like Sonic hedgehog, Contra) so you always wanted to be the first to unlock it or tell yr friends what the perfect ending was.
Some games were so annoyingly tough with [censored]controls like... Bart vs Space Mutants for Sega Megadrive. I still have nightmares about that game.