There's a billion, but one that comes to mind for me was the second X-Men game on the Genesis. There had been several X-men games on various platforms; none were great, and some were atrocious. So I wasn't expecting jack shit from this one, especially when the game randomly throws you into the first level without any menu screen or anything. But if you stay with it, holy shit it becomes a lot of fun. The characters' different powers actually worked correctly for once, and getting to play as Magneto was especially boss.
Kahran Ramsus said:
Earthbound. The marketing of it basically begged me not to play it
I still remember that bullshit. "This game STINKS!" So naturally it didn't sell worth a damn, and years later we still can't get official ports of any other entries from the series. Thanks, assholes. Advertising your game with ugly, reeking scratch-n-sniff cards that are designed to be repellant, fucking brilliant.