I think the only SNES game I've ever beaten is Super Mario World. Yoshi's Island and Super Metroid are way better, but the savefile got corrupted somehow, specially infuriating on Yoshi's Island case because I was two levels away from beating the game. I would also consider Chrono Trigger for this, but I played the DS version, so I don't know if it counts.
Anyway, best SNES game is Yoshi's Island.










