8.1
http://www.gamespot.com/gamecube/action/zeldafourswords/review.html
"It's not too surprising that it took Nintendo developing a game itself for the whole connectivity idea to really crystallize. The keys to the success of this game is that the game is inherently really good, with or without the hardware novelty. But, to be fair, if you only play Four Swords Adventures by yourself, you won't be getting the full experience. If you've been waiting for a truly compelling reason to invest in a GameCube-to-GBA link cable, this is probably it."
http://www.gamespot.com/gamecube/action/zeldafourswords/review.html
"It's not too surprising that it took Nintendo developing a game itself for the whole connectivity idea to really crystallize. The keys to the success of this game is that the game is inherently really good, with or without the hardware novelty. But, to be fair, if you only play Four Swords Adventures by yourself, you won't be getting the full experience. If you've been waiting for a truly compelling reason to invest in a GameCube-to-GBA link cable, this is probably it."