Super Mario Bros. 3 may be the popular choice for greatest Mario game, but the honor here goes to Super Mario World. World injected Mario with a million gallons of technicolor paint, providing a far more attractive world than any previous game in the series had been able to. The graphics grabbed anyone who saw them and demanded that they play this game. And underneath that was the most solid combination of Mario mechanics and power-ups ever conceived, with the fire flower and cape feather providing perfect counterpoints to one another. And underneath that was the most varied and complex level design ever featured in the series, with secrets, shortcuts and mysteries everywhere. It was—and still is—the standard.
Super Mario World (1990)