Sonic & All-Stars Racing Transformed is the sequel to Sonic & Sega All-Stars Racing, the fourth installment in the Sega Superstars series, and the eighth racing game in the Sonic the Hedgehog series.
Sonic & All-Stars Racing Transformed is a mascot-based racing game in which players race against each other using characters from various Sega franchises, although it features many new mechanics and improvements from the last game. The most obvious is that, at certain points in a race, vehicles can alternate between car, boat and plane modes. The car mode handles similarly to the previous game, in which players can earn boost by drifting around corners or performing tricks whilst in the air. Boat mode features true boating physics, requiring players to consider their vehicle's turbulence. They may also be affected by waves made in the water, some of which can be used to leap into the air and perform stunts. Plane mode, the fastest of the three forms, gives players the freedom to move both vertically and horizontally. Like the other modes, players can 'air-drift' around corners to earn boost and can also perform rolls to quickly adjust their position, earning boost for narrowly dodging obstacles. Players alternate between these modes by driving through blue transformation gates. Certain tracks in the game terraform as players proceed through them, offering different playstyles between each lap.
Several new varieties of weapons have been added, including explosive hot rod engines, freezing snowballs and swarms of wasps that appear at the front of the pack. All-Star Moves return from the previous title, though these are awarded slightly differently compared to the last game, and can now be used in online multiplayer. During races, players can collect star tokens, found scattered around the course or earned by attacking opponents, which can be spent in a slot machine between events to earn random bonuses, such as enhanced items or faster recovery from certain weapons.
The main campaign is the Career Mode which, along with returning features such as Grand Prix, Time Attack and Single Race, mainly revolves around the World Tour mode. This mode involves going through a branching series of events, ranging from standard races to various challenges, including earning time by drifting, maneuvering through traffic or fighting against large tanks. Completing these challenges on various difficulties earn stars which are used to open up new branches and unlock new characters and mods. Racing with each character in any mode earns XP which unlock modifications that alter the stats of each vehicle. The game features 16 new tracks inspired by games like Super Monkey Ball, Panzer Dragoon, Golden Axe, After Burner and Burning Rangers, as well as four returning locations from the first game and mirror versions of each track. The game also features online multiplayer in all versions and four player split-screen multiplayer for the console versions. Some of the career modes can also be played in split-screen multiplayer. The Wii U version also features unique minigames and features that utilize the Wii U GamePad and can support up to five players via split-screen.