Crash Nitro Kart is a racing game in which the player controls characters from the Crash Bandicoot universe, most of whom race in karts. While racing, the player can accelerate, steer, reverse, brake, hop or use weapons and power-ups with the game controller's analog stick and buttons. Four distinct types of crates are scattered throughout the tracks and arenas of Crash Nitro Kart. "Item Crates" are marked with a question mark and usually come in sets of four. The player can obtain a weapon or power-up by driving through an Item Crate and breaking it apart. The player can only carry one weapon or power-up at a time. "Multiplier Crates" are marked with an "X" and are usually found in hard-to-reach spots on the tracks. These special crates contain three of a certain weapon or power-up. "Wumpa Crates" are unmarked and carry "Wumpa Fruit" that strengthens the player's weapons and power-ups if ten of them are obtained. "Activation Crates" are marked with an exclamation point and don't give the player anything when they are driven through; instead, they activate either a trap that can slow down the other racers or a boost pad.
Boosting is an important part of Crash Nitro Kart's gameplay. When the player boosts, their kart will momentarily go slightly faster than its normal top speed. Boosts are achieved by driving over boost pads scattered across the tracks, pumping the gas at the starting line, and holding the gas button at the right time when being reset on the track. Another technique used for boosting is the "power slide". To execute a power slide, the player holds down one of the shoulder buttons to perform a hop and steer before the kart lands. While sliding, a curved "boost gauge" appears next to the player's kart. When the gauge goes from green to red, the player presses the opposite shoulder button to obtain a boost. The higher the boost gauge goes, the more powerful the boost will be.
Source: Wikipedia, "Crash Nitro Kart," available under the CC-BY-SA License.