Need for Speed Underground for the Game Boy Advance takes the street racing concept of the console/PC title and adapts it for the capabilities of the handheld platform.
The game's main mode is Underground Mode, where the player's goal is to make it to the top of the street racing scene from humble beginnings. The player starts with 10,000 credits and a choice of three cars. To progress, they must win races to earn money and unlock new cars and upgrade parts to make them available for purchase.
In each night of racing, the player must challenge one of the other racers that is slightly above them in the rankings. The race track and parameters are then randomly chosen, and winning the race advances the player's ranking. As the player rises through the ranks, they can also challenge higher-ranked players, who will propose a specific set of track, number of laps, and number of opponents.
The game features four types of racing: Circuit, Sprint, Drag, and Drift. In Circuit mode, the goal is to complete a set number of laps before opponents. In Sprint mode, it's about reaching a set point on the track as fast as possible. Drag mode involves short, straight tracks with manual transmission, requiring precise shifting to avoid engine burnout or losing speed. Drift mode rewards stylishly sliding around corners while avoiding crashes.
More than sixty races must be won to complete Underground Mode. Between races, cars can be traded and upgraded. There are 14 different cars available, and a variety of functional and visual upgrades, including engines, turbos, transmission, tires, brakes, bumpers, hoods, rims, paint jobs, and vinyls.