During gameplay press Select + Start + B + A all at the same time to go to the title screen.
Coins for Chao:
To get lots of coins for your Chao, play whatever you think is the the easiest level. Then when you beat the level and it advances to the next hold Select + Start + A + B then when you go to the Tiny Chao Garden. You should have as many coins as you received when you beat the level. Do this repeatedly then you can have lots of coins!
Old School Tag-A-Long:
Wanna have Tails follow you around like in Sonic The Hedgehog 2? Yes? Okay, here's what ya do. Go to game start, then highlight Sonic and press up. Move over to Tails and press down. Move over to Knuckles and press L. Move over to Amy and press R. Do this, and that lil' glory hog will follow you to death if you wish.
1000 "rings" (cough, ripoff!) gets your chao a trumpet. Give it to him to play-it (plays like crap). 2000 gets ya a rubber ducky. It just sits in the water. Waste of money. 8000 gets ya a T.V. it doesn't show up for three hours, or so I'm told.
The Moon Zone:
Get all the emeralds with all the characters and finish the game with Sonic to open the Moon Zone.
Double-Spring Power with Amy:
Smack a spring with Amy's hammer for twice the lift-off.
Thanks to Revolution readers Slimjimguy76, Jasonboy X, Slimjimguy76, littlerod, and Knuckles!