Sonic Heroes is a 3D platformer.[1] While the preceding Sonic Adventure games for the Dreamcast featured elements of action-adventure and exploration, Sonic Heroes focuses on linear platforming and action,[2][3] similar to the Sonic the Hedgehog games for the Sega Genesis.[4] The story is also simpler than those of the Sonic Adventure games. In it, series antagonist Doctor Eggman threatens to use a weapon to destroy the world and sends out legions of robots. Four groups of three characters from the franchise's history separately team up to put a stop to Eggman's plans.[5] The player navigates using one of the teams, who serve as the player characters.[2] The teams include Team Sonic, which consists of series regulars Sonic the Hedgehog, Miles "Tails" Prower, and Knuckles the Echidna; Team Dark, which includes Shadow the Hedgehog and Rouge the Bat from Sonic Adventure 2, and new character E-123 Omega (considered a spiritual successor to E-102 Gamma from Sonic Adventure); Team Rose, which has Amy Rose, Cream the Rabbit from Sonic Advance 2, and Big the Cat from Sonic Adventure; and Team Chaotix, consisting of Espio the Chameleon, Charmy Bee, and Vector the Crocodile from Knuckles' Chaotix.[5] Each team has its own campaign, called a story.[6] Each also represents a different difficulty. Amy's team, for example, is designed for beginners, while Shadow's is aimed at more experienced players.[4]
The game begins with a tutorial[6] followed by fourteen normal levels[4] and seven boss fights.[6] Gameplay is generally similar in each story: the player must race through levels to advance the story and collect rings for protection and lives.[2] Level themes vary[4] from beaches to casinos.[7] When the player reaches the end of a level, they are graded based on their performance; an "A" rank is highest, while an "E" is lowest.[3] Enemy robots are scattered around levels and must be defeated by jumping on them or other means of attack.[6] The level designs differ slightly between each story.[4] Espio, Charmy, and Vector's levels are distinguished from the other teams' because they are mission-based, requiring players to fulfill a specific objective, like collecting items, to clear a level.[8]
Teams contain three character types: Speed (such as Sonic), Flight (such as Tails), and Power (such as Knuckles), which the player toggles between.[8] Speed characters can perform attacks that allow them to lock onto enemies and objects, dash across lines of rings, and can form whirlwinds to climb up poles. Flight characters can temporarily fly and attack airborne enemies, while Power characters can break through objects and glide on gusts of air. By acquiring certain items or enemies, characters can level up, becoming more efficient when fighting enemies, though these level up items are lost if the player loses a life.[6]
By collecting keys hidden within levels and reaching the end of a level without getting hit, players can enter special stages.[9] In special stages, players dash across a tube, collecting spheres containing boost power while avoiding obstacles. There are two types of special stages: Bonus Challenge and Emerald Challenge. Bonus Challenges are optional and award the player with extra lives. Emerald Challenges task the player with catching a Chaos Emerald before it disappears.[6]
If players collect all seven Emeralds and clear each story, an additional Last Story is unlocked. The Last Story reveals the plot was orchestrated by Metal Sonic, Eggman's top enforcer and a robotic copy of Sonic, in an effort to destroy his namesake.[6] Outside the main game, players can unlock promotional trailers to view and music to listen to. The game also features a split screen multiplayer mode, in which two players can race or battle.[4] Challenges in the multiplayer mode include kart racing and collecting as many rings as possible.[9]
