6.4? Were you reviewing the right game?
MK 64 is part of a long and successful series of racing games, and certainly isnt a letdown. It offers a solid single player campaign and a constant challenge of beating your own time in time-trial.
However, the jewell in MK 64's crown is its multiplayer mode. With 4 people playing at once, the game offers a great oppertunity for tournaments or just plain fun in the form of great racing, good graphics and plenty of choice.
Overall, MK 64 is a must-have for someone who owns an N64. It is possibly in the top 10 games on the console. It truly deserves a rating of at least 9 out of 10, none of this 6.4 nonsence.