Knuckles' Chaotix

Knuckles' Chaotix is a side-scrolling platform game similar to earlier entries in the Sonic series . Unlike other Sonic games, players are tethered to a computer or human-controlled partner; the tether behaves like a rubber band and must be properly handled to maneuver through stages. There are five playable characters, each with their own unique abilities. Knuckles the Echidna can glide and climb walls; Mighty the Armadillo can perform a wall jump ; Espio the Chameleon can run along walls and ceilings; Vector the Crocodile can boost through the air and climb walls; and Charmy Bee can fly and hover.

There are two other partner characters, Heavy the Robot and Bomb, who hinder players' progress due to their slow or destructive nature, respectively. : 7–9 The story takes place on a mysterious island and follows the group's efforts to stop Doctor Robotnik and Metal Sonic from harnessing the power of the island's mythical Chaos Rings to satisfy their evil deeds. : 2 The game takes place over six levels called attractions. Each attraction is divided into five acts; the fifth ends in a boss fight with Robotnik and one of his large robots.

Each act has a different time of day decor, such as morning, noon, evening, and night. Like earlier Sonic games, players collect rings, jump to perform a spin attack to defeat enemies, and can perform a spin dash on the ground to gain speed. : 10, 15 Power-ups include rings, shields, and speed shoes. : 18 The partner system enables players to perform actions not seen in earlier Sonic games.

Players can call their partner if they are separated, which reunites them with the main character but costs 10 rings, or throw their partner to reach far platforms. If the partner is computer-controlled, the player can stop and anchor the partner to perform special moves such as "snapping" to a higher ledge or thrusting to gain speed. : 10–11 Before entering a stage, the player begins in a hub world where they choose a partner and level. Bonus stages are hidden throughout attractions, and can also be triggered by obtaining 20 or more rings and finding one of the giant golden rings hidden away in each level.

: 15 In the bonus levels, the player is free-falling and picks up power-ups. : 19 Special stages are reached by finishing a level with 50 or more rings. In these stages, the player collects blue spheres in a forward-scrolling platformer to earn a Chaos Ring. : 22 Collecting all Chaos Rings unlocks the "good" ending, in which Sonic and Tails are seen with the Chaotix, who have freed the island from Robotnik.