For anyone not joking about that, a pirate game is a game made by an unlicensed and unnamed publisher, most of which are in Hong Kong, and sell hacks, ports, or just games not readily available in that region. Since most areas still only have the NES, pirate companies make newer games for that system, as well as originals, like Somari, Kart Fighter, Mario World, and Tekken 2. But sicne these aren't made by Nintendo or any of the real copyright holders, they are pirate games. As I said, the game is a good one for what it is.