Good article from Nintendojo

[Dark Jaguar]

Actually, I never once played an NES game that only saved high scores. They were all wiped clean and restored to the "default" high score after shutting them off. Maybe there were some acceptions, but I'm fairly sure the only games they bothered putting save batteries in were ones that saved actual progress. All the Mario games, the DK games, all the arcadish games that are on the cards right now, as well as the ones in Animal Crossing, none saved high scores. They were only kept until the power was cut off. By the way, I REALLY wish the US version of Animal Crossing would let us unlock Super Mario Bros and The Legend of Zelda...