Very dirty and immature, but being one the best 3D platformers ever made more than makes up for it. An instant classic.
The game stars Conker, the squirrel that most people assumed was so nice (especially if you played Diddy Kong Racing). Conker is at a bar, drinks too much and ends up taking the wrong way home. His mission: find a way back home and become a millionaire along the way; how will he get there? With the help of a massive cast of laugh-out-loud characters.
The story is chapter-based. You go through different sections of a chapter which takes place in a certain area (e.x. a garden, Prehistoric times, the Matrix, etc.). Progress is made by helping various characters with any problems they may have, ranging from bringing a lonely king bee to his true love to feeding a mouse cheese until he explodes... literally.
The game is well-written with great dialogue and hilarity every step of the way. And the actual game is very challenging and tutorials are presented in a unique way. For example, when you die for the first time, the cat-hating Grim Reaper lets you know you have lives like cats, which is why he hates them.
The game's strongest suit is the multiplayer, with a band of modes like War (Deathmatch... nuff said), Beach (infiltrate the enemy base), Capture the Flag, and so on. There is four-player splitscreen multiplayer and sixteen-player games with adjustable AI.
Overall, this is truly one of, if not, the best 3D platformer made in recent memory and the best Rare has to offer. It's a real shame this great company won't be around to make more awesome games. All I hope is that Microsoft will do Conker, and Banjo justice by keeping them great and not screwing it up in any way.