Continue Gameplay
Locate the hidden egg at the end of Level 1. Just before the G sign, jump up to find the egg. Smash it and get the Hudson Bee logo. Now, at the game over screen, hold Up + A + Select and press Start.

Island Select
Let the game get to the Title screen, then reset the system. At the Title screen, press Right, Left, Right, Left, A, B, A, B.