The color-coded eggs themselves are another gameplay element. As Billy runs over fruit while holding an egg, the egg gains maturity and gets larger. When the egg's maturity gauge completely fills, the egg flashes and is ready to hatch. Then Billy can hatch the eggs, which can contain helper animals, character power-ups, and extra lives. With variables such as egg size, helper animals, and personal power-ups, "Billy Hatcher" can be played in many ways. Different animals can come out of the same eggs, and some creatures are vital to progressing through certain challenges.