Sonic Riders: Zero Gravity

Sonic Riders: Zero Gravity is a hoverboard racing video game developed by Sonic Team and published by Sega for the PlayStation 2 and Wii. It is the fifth racing game in the Sonic the Hedgehog series, and the second entry in the Sonic Riders trilogy, a spin-off of the main series. A sequel, Sonic Free Riders, was released for the Xbox 360 in 2010.

Gameplay in Zero Gravity is largely like its predecessor, with characters racing on different types of hovercraft called "Extreme Gear". In addition to the mechanics from the previous game, Zero Gravity adds a new gameplay system based around gravity that replaces the predecessor's "fuel" system. During the race, performing tricks and other actions will increase a character's Gravity Points, or GP. If players have accrued enough GP by the time, they enter certain areas of the track, they will enter a Zero-Gravity Zone, where they can perform one of two maneuvers. A Gravity Dive will create a small black hole that points gravity forward down the track, giving the player a powerful free-fall boost that is further augmented by striking objects in the vicinity that the hole displaces, such as cars or signs. Alternatively, Gravity Control will alter the gravity of the course, allowing players to reach otherwise-inaccessible areas and shortcuts.

The game includes a total of 16 racetracks, spread across eight areas with two tracks each, which are unlocked via story progression. A total of 18 playable characters can be unlocked, including guest characters from Billy Hatcher and the Giant Egg, Nights into Dreams, and Samba de Amigo.

Zero Gravity once again features two story campaigns, "Heroes" and "Babylon", which intersect with one another to create a single narrative. Three new game modes have also been added: Survival Mode, Survival Relay, and Survival Ball.