Although the games share the same name, their tone and focus can vary significantly. For example, in some games the cars can suffer mechanical and visual damage, while in other games the cars cannot be damaged at all; in some games the software simulates real-car behavior (physics), while in others there are more forgiving physics.
With the release of Need for Speed: Underground, the series shifted from racing sports cars on scenic point-to-point tracks, to an import/tuner subculture, and street racing in an urban setting. To date, this theme has remained prevalent in most of the following games.
Need for Speed: Shift and its sequel took a simulator approach to racing, featuring closed-circuit racing on real tracks like the Nürburgring and the Laguna Seca, and fictional street circuits in cities like London and Chicago. The car lists include a combination of exotics, sports cars, and tuners in addition to special race cars.
Most of the games in the franchise include police pursuits in some form or other. In some of the games featuring police pursuit, the player can play as either the felon or the cop. The concepts of drifting and dragging were introduced in Need for Speed: Underground. These new mechanics are included in the tournament/career mode aside from the regular street races. In drift races, the player must defeat other racers by totaling the most points, earned by the length and timing of the drift made by the player's vehicle. In drag races, the player must finish first to win the race, though if the player crashes into an obstacle, the race ends.
The concept of car tuning evolved with each new game, from focusing mainly on the mechanics of the car to including how the car looks. Each game has car tuning which can set options for items like ABS, traction control, or downforce, or for upgrading parts like the engine or gearbox. Visual tuning of the player's car becomes important in tournament/career mode after the release of Need for Speed: Underground 2, when the appearance is rated from zero to ten points. When a car attains a high enough visual rating, the vehicle is eligible to be on the cover of a fictional magazine.
Like all racing games, the Need for Speed series features a list of cars, modeled and named after actual cars. Cars in the franchise are divided into four categories: exotic cars, muscle cars, tuners, and special vehicles. Exotic cars feature high performance, expensive cars like the Lamborghini Murciélago, Mercedes-Benz SLR McLaren, Chevrolet Corvette and theFord GT; muscle cars refer to the Ford Mustang, Dodge Challenger and the Chevrolet Camaro; while tuner cars are cars like the Nissan Skyline and the Mitsubishi Lancer Evolution. The special vehicles are civilian and police cars that are available for use in some games, such as the Ford Crown Victoria in Need for Speed: Hot Pursuit and garbage trucks, fire engines and taxis in Need for Speed: Carbon.
Originally the series took place in international settings, such as race tracks in Australia, Europe, and Africa. Beginning with Underground, the series has taken place in fictional metropolitan cities. The first game featured traffic on "head to head" mode, while later games traffic can be toggled on and off, and starting with Underground, traffic is a fixed obstacle.