Quite possibly the best Sonic game for the GBA. A true keeper for diehard fans of the franchise.
Graphics: I'm going to be pretty straight foreward when I say this. Sonic Battle has awesome graphics! Yes, they are the same style of graphics as the Advance series but SB's graphics have a certain....depth to them that makes them stand out. The individual special attacks of the characters look detailed and real suck as Rouge's special attack kick. I will say though that the graphics of this game have their downsides too. The battle graphics are great but the overworld character graphics seem rushed and not all that well drawn. In my opinion Sonic Team should have balanced out the graphical beauty of the characters and the surroundings. There are areas where the graphics tend to be a bit fuzzy or uneven but otherwise unnoticable when playing.
Gameplay: Not much to say about the gameplay. It's pretty clean and simple and not at all scratchy. The addition to the detail of the individual character's speed level adds uniqueness to the Gameplay but at the same time decreases the liking of certain characters cause some (like Chaos for example) can not be used in a fight at all due to slow speed. Knuckles is made hard to fight as because his controls are somewhat klunky and may take a lot of practice to get used to. All in all, pretty decent gameplay I say.
Sound: The battle music for this game is pretty good for this kind of fighting game. While they are catchy in their own ways they remain invisable to your ears so you pay more attention to your fight than the music but at the same time am still able to hear the music and fight to it. The sound effects fits perfectly to the actions they are associated with and give the player a sense of being in the battles as the character they're playing as. Overall, the sound is very nicely done.
In over all value, this game is a must for diehard Sonic fans and easy for them to adjust to. The addition of unlockable Mini Games was a nice addition, the only downside was that all but 1 of them are multiplayer and can only be played with 2 or more people. That gives a small frown to the game but doesn't deteriate much from the overall score.