Successfully complete all puzzles in special mode.
Chaos in the puzzle
Finish all 25 puzzles in stage challenge mode to have a Chao from Sonic Adventure replace the Chu-Chus.
Try out the Dreamkey Beta Browser
The beta of the new browser, Dreamkey, is used to view the Chu Chu Rocket webpage! Just go onto any page on the Chu Chu Rocket webpage and push Ctrl+O on your keyboard. A jump-to a window will appear and you may type in an address to view. This will only work if you have a Dreamcast keyboard, though.
Taunt opponents
Press L or R during the battle games to taunt your opponent. Hold L or R to choose which taunt to use. You can also taunt even after you have won at the congratulations screen.
Save pictures from the web
You can save pictures onto your VMU while using Chu Chu's Dreamkey browser. Place the cursor over the desired picture and press X + A on the controller.
Sonic Adventure Chaos
Successfully complete each of the twenty-five challenge mode levels to transform the mice into Chaos from Sonic Adventure.
NiGHTS angels
Successfully complete each of the twenty-five mania mode levels to transform the mice into angels from NiGHTS.
