Mario Kart it's not! Touchy controls, lame powerups, and fuzzy graphics detract from a game with potential.
Graphics
The graphics might be half decent if not for the fuzzy images and excessive color bleeding. The entire game appears as if you were looking through binoculars that were out of focus and backwards. The developers appear to have tried to make the graphics highly detailed and, in doing so, made the images too busy. Everything is messy and difficult to discern carts from the background and track, and the track from the scenery. The game would have been better with simpler graphics or cell-shading, though I'm not sure if this was possible on the N64 at the time.
Sound
The sounds would be great with authentic samples of the Disney characters voices. However, they end up getting repetitive and intrusive, demoting their rating.
Gameplay
The powerups were unintuitive even after we Gamefaq-ed Mickey's Speedway. We couldn't figure out how to properly shoot the remote-control car or airplane (the homing missiles of the game, we thought), and the power-up icons were hard to discern from one another due to the fuzzy graphics. The courses were tough, with many blind corners and crests, and more representative of NASCAR than NAS-KART. However, there is great variety in the number of courses offered. We're still not sure if the rings that are all over the courses and you are supposed to collect actually had any effect on our driving ability.
Summary
Avoid the game, get a next-gen or last-gen system, and play Mario Kart. Unlock the secrets. If you want more Mario Kart, play something else for awhile or go outdoors, then come back to it instead of pacifying your Kart-racing urges with this squint-inducing work.