Sega's first third-party release since its decision to become a software-only company is ChuChu Rocket for the Game Boy Advance, and outside of a few control quirks, the portable version of ChuChu is right on par with the Dreamcast release.

　　ChuChu is all about guiding mice into rocket ships. The mice come out of holes, and players must guide them by placing arrows on the playfield. There are also three other players trying to do the same thing. On top of all that, there are cats, which kill a chunk of the mice the player is guiding if they reach the player's rocket, and special mice that deliver different effects, such as slowing down the game, switching the positions of all the rockets, and so on. Aside from the main battle mode, there is also a one-player puzzle mode, which gives players different challenges, such as guiding all the mice into the rocket or killing them all with cats before time runs out.

　　The Dreamcast version had very intuitive control. The analog pad moved the player's cursor, and the four face buttons were assigned to the four different directional arrows. With the GBA's two face buttons, some changes had to be made. The default control scheme puts the up arrow on A and the down arrow on B. Pushing a button multiple times will rotate the arrow until players get the one they like. Another scheme lets players hold A, then push the d-pad in the direction of the arrow they want. The final mode, called pro, uses A and B for up and down arrows, and the two triggers for left and right. None of them is perfect, but they all work reasonably well once players get used to them.

　　The game features a level creator, similar to the one found in the Dreamcast version, and some of the best user-made levels are already included in the game. Players can also create their own characters to replace the cats and mice--the game comes stock with a few options, including snowmen, cows, and balloons to replace the mice, and fire, UFOs, and pins to replace the cats.

　　The Japanese version of ChuChu Rocket contains a full English language mode and is scheduled to come to the US when the system reaches North America on June 11.