Billy Hatcher and the Giant Egg Cheats
Finish one of the following tasks to unlock an emblem: complete all missions with an "S" rank; collect all coins; complete all missions; unlock the entire Egg Gallery.
Game Boy Advance eggs
Locate and hatch the bonus eggs below in that particular location to unlock a downloadable Game Boy Advance mini-game. Chu Chu Rocket: Pirates island 2 Nights: Circus Park 2 Billy Hatcher Hyper Shoot Easy: Dino Mountain 2 Billy Hatcher Hyper Shoot Hard: Sand Ruin 2 Puyo Pop: Blizzard Castle 3
Getting easy rolls
Don't try to beat the egg you roll down the point you have to catch it before it roll off a cliff, roll with the egg by jumping then push R while rolling on the tracks.
Unlock Bantam Scrambled
Finish the Save Bantam mission (Blizzard Castle mission 4).
Collect all five coins in each world to have access to one Sonic egg in every world.
Unlock Rolly Roll
Finish the Save Rolly mission (Pirate Island mission 4).
Unlock Chick Poacher
Finish the Save Chick mission (Dino Mountain mission 4).