XG has gone a long why for the N64. but this should be something everyone should pick up.
As most Racing games there is really no story line then just to have fun. now for the N64 I mostly play with friends but playing single with hard difficulty bots is still fun. Now if you beaten it on Easy don't stop, there are more levels to unlock when you play on different difficulties.
Controls are working smoothly with the N64, I like how Z is the gas then a cause its easy to press stuff like turbo or use weapon you picked up. Design for its time is done really well and I love how it works out. I also like how there are 3 sections to a track. there are 12 tracks times 3 you have 36 races to do. Bikes are great to unlock and its even better to play it 4 player in racing or battle modes.
As for bad, there is only one thing I have to say. when in the air the air bubble I call it is too small and tend to hit it when flying into the air, when doing so it tends to stop you or make you fly backwards. There was one time I fell through the floor. The same goes for tunnels, when your bike is not in the right place it will, lets say, make you stop and fly backwards.
Overall this game is something I enjoy and everyone should. Its not the best game out there for the N64 but at least its something to add to your collection.