Out of all N64 titles, this one dominates and sets a standard for them. Something every gamer should buy.
Gameplay - You play as Banjo, a bear, and Kazooie, a bird that rides along in Banjo's backpack, as you go through the lair of the evil witch, Gruntilda (or Grunty for short, as she likes to be called), and save Banjo's sister, Tootie. Along the way, you pick up magical jigsaw pieces (jiggies) that allow you to complete paintings that will unlock more worlds in Grunty's lair for you to explore. Bottles, your mole friend, will assist you by giving you new attacks and advice, and Mumbo, a skull-headed shaman, will transform your character into all sorts of freakish creatures (well, more like just regular animals, but they look really weird...). There's a slew of interesting characters to find here, each one with a quirky and interesting personality. Finding jiggies and other collectibles gives the game a purpose to keep you going, and often calls for backtracking to find another mission and earn that last jiggy you need to complete the painting and continue on. While no boss fights in this game, other than the final boss, you're still left satisfied when fighting the enemies using the very stable controls. Collecting "jinjos" also leads to great rewards, though I forget what those rewards are...I think you need them to beat Grunty, but I can't remember what they're for (they were important, I remember that...). Each new area takes on its own theme apart from the castle. Some are a little cliche, but are still wonderfully and thoughtfully designed. Basically, the gameplay is just sheer, solid fun.
Graphics - For the Nintendo 64, these graphics are awesome. Sure, not the best, considering what the system can do, but they're quite solid. Character design was done right, which also adds to their personality, and gives their appearance something for the eyes to desire (and not want to be stabbed out instead). The worlds, like I said, are intuitively designed, each one coming to life. Lighting effects and movements flow smoothly. The only problem, as stated, is that the graphics aren't totally the best.
Sound - Though somewhat repetetive, music in the game also gives it that flavor. When you hit an enemy, you feel that it's monumental that you defeated it, considering how lifelike a lot of things in the game are, due to the sounds and actions that each creature creates. The music is basically the high point. The only real issue is that there's no real voice acting. Characters talk while a little replica of their heads moves up and down and a repetetive sound comes out. The good news is that that noise is different for each character.
Value - The single player is epic and inspiring. Once that's done, there may be some replay value to find every jiggy and jinjo. There's also a magical sand castle that lets you input codes to unlock special Easter Eggs (literally, actual eggs). But really...other than experimenting with the castle, and the amazing single player, there's not much to come back to (though, at the point in time when the game was released, that wasn't much of an issue).
This is one of those games that'll be remembered in history as one of the games that every gamer should at least check out, whether they own an N64 or not.