The player controls a white car that travels up (and then down) a tricky landscape filled with water, bumps, trees, and enemy vehicles. Cash is earned by completing levels, with an initial $10,000 available. These funds are spent at garages to buy extra fuel, repair the car's armour, and put add-ons for the car. These include a turbo-jump (allowing the car to get airborne unassisted, rather than relying on jumps) and water-proofing.
Source: Wikipedia, "5th Gear (computer game)," available under the CC-BY-SA License.