Infinite Lives and Invincibility
When you roll an egg over fruit, the hatching meter will increase, and when it is full, you can hatch the egg by pressing the "R" button. A hatched egg will sometimes produce power-up items, such as a free life. When you hatch a free life, go back to the area where you found the egg and hatch it over again to earn as many lives as you like. The same technique can be used on Sonic Eggs, which appear in a level after you have beaten it once and bestow invincibility.
Action Replay Codes
If you have an American Action Replay, use these codes with "Billy Hatcher &the Giant Egg" to make playing easy. You must first put the Action Replay disc and memory card into your GameCube and then enter the Master Code to configure the device to this particular game. Note that using an Action Replay can cause instability, so use a separate save file for your game with cheats.
Master code:
1GAV-A2HZ-2QCPA
AJXQ-DFYU-A6JQ6
FUGU-9JMQ-2WVXT
For infinite lives enter:
X7MT-N6M6-1U5D9
CVCW-KWB7-569BC
For infinite health enter:
KNXC-RJBU-P0R1F
X9A7-1NBB-720PX
To unlock all of the levels enter:
VBFQ-TFGJ-JNFQJ
9EP4-P3D2-QXDEM
More Characters and Missions
Saving Billy's friends Rolly, Chick and Bantam will unlock those characters in Mission Mode. Complete Pirate Island Mission 4 to unlock Rolly, Dino Mountain Mission 4 to unlock Chick and Blizzard Castle Mission 4 to unlock Bantam. Although the additional characters have different body types, gameplay and controls for them are identical to Billy. However, the characters have their own mission for every level in the game, making eight missions in total for every level once all the characters have been unlocked.
Gameboy Advance Games
"Billy Hatcher &the Giant Egg" features compatibility with the Gameboy Advance and Gameboy Advance SP using the Gameboy Advance Link Cable. This allows players to download Sega games directly to their Gameboy from the "Billy Hatcher" game disc and store them on their Gameboy until they turn off the system. However, the games must first be unlocked by completing missions. Complete Dino Mountain Mission 2 to unlock "Billy Hatcher Hyper Shoot" on easy mode, and Sand Ruin Mission 2 for hard Mode. Complete Pirate Island Mission 2 for "Chu Chu Rocket," Circus Park Mission 2 for "Nights" and Blizzard Castle Mission 3 for "Puyo Pop."