This is a very fun, pretty polished hidden gem from this series! The combat mechanics are very simple, but they utilize a very interesting special moves system where each stock you can block one of the three types of moves. The 3D arenas are also really cool for a GBA game, especially if playing it on a handheld like a GBA or 3DS where it won't look too chunky.

The story is pretty good too, as it's basically just "Sonic and Co. literally raise a child together". You can imagine pretty well how that goes, although it tying back into SA2's story with Gerald Robotnik and Shadow was pretty cool. Really goes to show how much SEGA was committing to the continuity of this series back in the day.

The main appeal of this game is customizing the robot playable character that the characters raise, Emerl. He has a super cool ability where you can equip him with moves from other characters you get from fighting those characters, where the only issue is that they don't drop enough. From what I've seen, it's nearly impossible to get all of the cards in a reasonable time, which is my main critique of the game. After trying (in vain) for about 2 hours to get anywhere in the Virtual Training mode for new cards, I just gave up and cheated them in because I have better things to do.

Overall though, really fun time that gets a solid recommendation for me! Good length, good difficulty, genuinely just a really fun, although not perfect, game.