The stage is based off of a theme park, and every part of it is designed to give off a magical feel, with neon lights and sparkly objects everywhere. This stage is playable as Sonic, Amy, and Big as their fifth, first, and first stages, respectively.
After being shot down in the Tornado, Sonic is looking for Tails, when Amy finds him, and follows him to Twinkle Park, where she gets excited when she notices a sign stating that "cute couples can get in free". She instantly enters the park, much to Sonic's dismay, who is forced to chase after her.
Big's reason for coming to Twinkle Park was that he followed Froggy there, and must try to catch him in the pool in the park.
Sonic starts out on a race track with enemies driving bumper cars around. Sonic must defeat an enemy and steal its bumper car, then take to the track. After this area, Sonic jumps in a roller coaster, then proceeds to run through a variety of amusement park obstacles built around a castle.
Amy starts out by the large swimming pool where she must push three buttons in a certain amount of time to proceed. Afterwards, she heads into the castle, which turns out to be a giant house of mirrors. Afterwards, she proceeds through a short section of Sonic's level before finishing and grabbing the balloon.
Big also starts out in the giant swimming pool area, where he is tasked with catching Froggy. The area is very small, and there aren't many fish here, which can make catching large fish for Big's "B" and "A" rank missions somewhat difficult.
Many people associate this stage with Amy due to it's important in the overlapping parts of her's and Sonic's story as well as it being her first stage and it being the only stage to have a section that Sonic does not enter.
When riding on a bumper car, the car speeds up and accelerates faster the more Rings that are collected, eventually capping out at ninety nine. Collecting large amounts of Rings is essential if the player wants to travel at high speeds.
After a certain point, on the grass triangle outside Twinkle Park, the Cart Pass becomes available for all characters. This allows characters not otherwise available (a.k.a Tails) to participate in the bumper car section.
Tails, Knuckles, and E-102 Gamma can also get into Twinkle Park through the use of glitches and/or debug mode. They will start in the bumper car's section; however, the game will put them in an area below the starting point, falling into a bottomless pit forever. If Knuckles or Gamma glides/hovers long enough, they will eventually find the track and can proceed into the level (without hacks, Tails cannot do this, as his flying ability does not last long enough). If the player attempts to enter a bumper car, or attempts to use the bowling launcher with any character besides Sonic, the game will crash.
In Sonic's story, a major short cut can be found right after the roller coaster section. By holding left as the player is ejected from the coaster, he/she will not fall down the hole. The player can then run backwards and fall off the edge, landing on a hidden platform. From here, he/she can Spin Dash to the swimming pool, thus skipping a large portion of the stage. This helps immensely with Sonic's A-rank mission.