|| This article needs either a photograph or screenshot of the sub-game in the Dreamcast and SADX versions to improve its quality.
Twinkle Circuit is a sub-game in Sonic Adventure located near the entrance to Twinkle Park. Sonic, Amy and Big can access it after they clear Twinkle Park. Tails, Knuckles and Gamma can access it with a cart pass, which can be found in Station Square's Central District after completing their respective storylines. All characters may also access this sub-game in Trial mode.
Based on Sonic's first section of Twinkle Park, Twinkle Circuit is a 3-lap bumper car circuit filled with Rings, jumps and Speed Boosters where the objective is to clear all three laps as quickly as possible. Collecting Rings will increase the car's top speed and acceleration, eventually capping out at 99, and driving over a Speed Booster will catapult the car forward in a straight line. Crossing the jumps in the course can be tricky; depending on the speed and angle the player approaches the jumps at, they can fly off at an angle and fall off the circuit, losing a life; if they are travelling slowly enough, they may not be able to make the jump and fall.
A total of two Emblems can be won from this sub-game. The first Emblem is won by simply finishing the course, while the second is won by achieving a certain time. The music that plays in this sub-game features an instrumental cover of the chorus from Sonic's theme, It Doesn't Matter, at a certain point.
Each character drives a different-coloured bumper car with varying top speed, acceleration and handling. The possible car colours are listed below:
Typically, there is only one course available in the game, but five others exist in Sonic Adventure's data. One of the five courses was released as a VMU download for the Dreamcast release as the "Samba GP" course, and used an instrumental version of Super Sonic Racing from Sonic R if Sonic entered the course. The other four courses are completely unused, requiring the player to modify the Act ID via cheats in order to access them.