Sonic Battle

Battles are fought in 3D arenas with up to four players. Each character has a set of attacks and abilities. Most attacks are used with B, including the combo (1st, 2nd, and 3rd Attack), Air Attack, Upper Attack (used to knock opponents straight up), Heavy Attack (used to knock opponents away), and Aim Attack (used to pursue an opponent after the Heavy Attack). The A button is used to jump, and the L button lets the player block attacks, or heal damage if the button is held.

The playable characters also have unique special moves, the three types being Shot, Power, and Set. Shot moves center around using a projectile to damage the opponent from a distance. Power moves focus on dealing damage quickly in a single move. Trap moves generally involve using a type of bomb to surprise-attack the enemy.

While studying the diary of his grandfather, Professor Gerald Robotnik, Dr. Eggman learns of an artifact Gerald had unearthed: a 4000-year-old sentient weapon called the Gizoid created by an ancient civilization. Eggman attempts to get the dormant Gizoid to work properly, but is unsuccessful and abandons it at Emerald Beach. Sonic the Hedgehog finds the Gizoid, which activates and develops a link with him after Sonic demonstrates his abilities.

The Gizoid, which Sonic names Emerl due to its ability to use the Chaos Emeralds, demonstrates the power to perfectly replicate any moves it sees and quickly gets wrapped up in the affairs of Sonic's friends, allies and rivals. Through his encounters with Miles "Tails" Prower, Rouge the Bat, Knuckles the Echidna, Amy Rose, Cream the Rabbit, and Shadow the Hedgehog, Emerl learns of the world and of concepts like friendship. As they train together, the group discovers that Emerl becomes stronger and develops more sentience with each Chaos Emerald which he obtains, and begin searching for the remaining Emeralds to help the robot develop. While searching, they are repeatedly attacked by the forces of Eggman, who now wants to retrieve the weapon, including a rebuilt E-102 Gamma and a series of imperfect Emerl duplicates under the name "E-121 Phi".

The game was officially announced at the 2003 Electronic Entertainment Expo (E3) and Tokyo Game Show, both of which featured playable demos. The game was released in late-2003 in Japan as part of the "Year of Sonic", and early-2004 by THQ in the United States following a deal between both companies. Internationally, the game was published by Sega Europe and distributed by THQ as part of a Game Boy Advance co-publishing agreement made by the two companies. Sonic Battle was adapted in the second season of the 2003 Sonic the Hedgehog anime television series Sonic X, with the story arc being a loose adaptation for the show.

The game received generally mixed reviews from critics, according to review aggregator site Metacritic. While some critics praised the game's "surprisingly deep arena-fighting gameplay", graphics, and multiplayer mode, others dismissed it for its "limited moveset" and use of 2D sprites on a 3D fighting arena.

IGN gave the game a positive review, saying "It does try hard to be what Smash Bros. is, and even though the game doesn't quite reach the same status Nintendo and HAL created for the Nintendo consoles, Sonic Battle has enough stuff to make it one of the top original fighters on the Game Boy Advance system." GameSpy also gave a positive review, saying "A solid and pleasantly deep arena beat-'em-up with lots of longevity, and though the presence of the Hedgehog and his posse adds absolutely nothing to the game, it's nice to see them getting work in these tough economic times." Nintendo Power gave a more mixed review, saying, "Moves are limited, but the overall experience is tons of fun."