Technically, I beat Rhythm Heaven Fever. I've already cleared all games, but now I'm trying to get a superb rating on all of them to get my chance on having a perfect. It's gonna be very very challenging, and god knows how long it'll be, but let lightning strike me if the game isn't addicting. (Gonna play the game twice as well. Ordered the Europaen version called Beat the Beat: Rhythm Paradise so I can play the whole game with the Japanese soundtrack on.)
Also, maybe Punch-Out counts? I just beat the champion, so I've already faced everyone. (sans the secret challenger.) I mean, THERE is still title defense mode where I have to fight and defend my title against every single boxer I faced, but I don't know if you could consider that post-game or half of the game.