All players should note that the Kirby games are designed for younger kids, and as a result the games are bright, cheery and very easy to complete. Kirby games are fun, but some people may be put off by all the cuteness. If you cannot enjoy Super Mario 64 because it is too cute, then I recommend staying away from Kirby 64. It could kill you.
Parents should have an easy conscience getting this for their younger kids. It's non-violent, mildly enjoyable, and entertaining. It is perfect for someone just getting into games, but games like Super Mario 64 and Super Mario Kart 64 are much better options.
Kirby fans will probably have mixed feelings about this game. Some will enjoy it because it's Kirby and hes so cute, others won't because it is a step back in gameplay and fun for the series. Kirby 64 has far less appeal outside its age range than the rest of the series.
Those looking for the main-quest multiplayer, a la Kirby's Super Star or Kirby's Dream Land 3 will be definitely disappointed.
Gamers in general would have more fun spending their money for Kirby's Super Star on the SNES, Kirby's Adventure on the NES and Kirby's Dream Land 2 on Game Boy to enjoy the best of the Kirby series.