Sonic Adventure 2: Battle was a game that came out on Ferbuary 12th 2002 for the Gamecube. It has essentially the same material from Sonic Adventure 2 for the Dreamcast released in 2001.
Sonic Adventure 2: Battle has the new battle option in multi-player mode. It has a Chao Garden where the player can raise and train chaos (small blob-like creatures) to race and fight karate.
- A Black Market has been added to the Chao Kindergarten. It was originally a limited feature of the website.
- Big the Cat's cameos have been removed from the stages, oftentimes with a ring. He is also replaced by a Dark Chao in the multiplayer mode. However, he can still be seen in cutscenes, but only on Dark Side and Final Story.
- Amy Rose, Chao Walker, Tikal, Metal Sonic, Dark Chao Walker and Chaos 0 are now available at the start of the multiplayer mode and have their own movesets. The characters were originally only selectable between "Hero" and "Dark", and bonus characters performed exactly like their 1P counterparts with no unique voices. The 2P Mode also has more stages and settings, and alternate costumes now give the character slightly different attributes.
- The unlockable costumes for Sonic, Shadow, Knuckles, Rouge, and Eggman have changed somewhat.
- Tails and Eggman's lock-on power now utilizes a faster system able to lock-on every 8 frames which was previously every 12 frames on the Dreamcast.
- The first frame of Knuckles' Spiral Upper attack, and Rouge's Screw Kick, has roughly double the reach on Dreamcast. This was removed in the GameCube version, leaving it with only the same reach as the rest of the move. Additionally, a few more objects were given immunity to those moves, most notably the safes around the perimeter of Security Hall.
- Treasure hunting has an additional level of detection - an exclamation point in a red action bubble will appear above a character's head once they are right within reach of the emerald or key.
- Chao Karate has been added to the Chao Stadium. The A-Life system has also been slightly enhanced, with all-around more accessible options.
- The VMU game Chao Adventure 2 has been replaced by the Tiny Chao Garden, available via GBA connection.
- Omochao no longer welcomes the player to Chao World.
- There is more music in the GameCube version. For example, the Dreamcast's Chao World theme was moved to the new Chao cave selection, and in its place is the Chao Racing menu theme from Sonic Adventure.
- Some of the game's graphics have been tweaked. The main characters have minor enhancements, but secondary characters and enemy models have been slightly downgraded. Inexplicably, some of the writing on the mechs has vanished as well.
- For example, in the Dreamcast version, many of the G.U.N. robots have blue fiery jets to keep them floating/moving; in the GameCube version, however, all that's left are the jet nozzles. In terms of side-characters, Amy's teeth are no longer prominent and Maria Robotnik's eyelashes were removed.
- Also in levels where lighting would pulse down the screen like in Egg Quarters, when you encounter the Egg Beetles, and Iron Gate when a security sector has been breached, the lights no longer pulse. Lighting in general (as well as shading and textures) were also adjusted, with some areas receiving more clarity and others being simplified.
- There are also some different visual effects altogether - for example, White Jungle did not originally have rain and instead had purple spores floating down. Graphical glitches were also reduced.
- Some of the level layouts and ranking requirements were adjusted for better flow.
- The intro is different showing the six main characters instead of just showing outer space with the game's logo.
- The title screen and the main menu screen are different and reorganized.
- Some posters in the stages have been changed or rearranged.
- The Hero and Dark Gardens were a little bit bigger in Dreamcast version. The Dark Garden in particular had a larger body of the blood-red water and the cave, as well as a ramp leading up to another tombstone in the original release.
- The Dreamcast version had the "Download Event" mode where the player could download various events, although to a far smaller scale than Sonic Adventure. Some features exclusive to the Dreamcast version include a Halloween and Christmas theme for the character outfits in 2P mode, as well as three additional race tracks. Features brought back to the GameCube release include a selectable Eggrobo racer and expanded character themes for the menus (which was noticeably missing Shadow).
- The Knuckles segment of the final level, Cannon's Core, is made easier due to boxes being placed in the areas where he gets air bubbles. When Knuckles takes in an air bubble he sinks a few inches. In the original version, taking in air would make him sink and touch the hazardous ground and take damage or lose a life. Because of the boxes in the GameCube version, Knuckles can take in the air bubbles without getting hurt.
- Some of the cutscenes have been altered slightly, either with camera angles or dialogue timing. One noticeable instance is the first encounter between Knuckles and Rouge - she has a different camera angle when she looks up at Eggman, and she screams at a different time when the Master Emerald is broken (overlapping Eggman's quiet exclamation). Her mouth just gapes open with no sound coming out.
- In the scene when Sonic jumps off the helicopter, he is now seen with his Soap shoes. In the Dreamcast release, he is briefly seen with his original shoes before switching them off-screen. The angles and lens flare are also different.
- In the GameCube version of the cutscene where Sonic and Shadow meet for the first time, the officers' voices are cut off short and over lap each other. In the Dreamcast version of the cutscene, the officers shout at Sonic in full sentences.
- When the President is speaking to Eggman, there seems to be a lag issue between their conversation on Eggman's screen showing several arm movements at one time.
- Right after Pyramid Cave, the Eggman symbols at the end of the level do not appear in the following cutscene.
- The cutscene where Rouge and Shadow meet up for the last time had a few changes such as shifting from Rouge's theme to Maria's theme.
- The song "Deeper" for the Death Chamber level removed the Sonic and Knuckles conversation lyrics and replaced it with a saxophone solo. The reason for this was most likely because Sonic says at the final lyric of the "conversation" "Ya damn right, Knuckles!"
- Japanese language settings are set as the default in the Japanese region, which was not the case in the Dreamcast version (similar to Sonic Adventure International).