To unlock all weapons and power-ups, pause the game while playing on the easier difficulty setting, then press UP(2), DOWN(2), LEFT, RIGHT, LEFT, RIGHT, L, R to unlock all weapons and power-ups. In the Japanese version of the game, press UP(2), DOWN(2), LEFT, RIGHT, LEFT, RIGHT, X, CIRCLE.
Unlock the following bonuses by performing the corresponding tasks:
BONUS - HOW TO UNLOCK Cube Attack in Gradius 3 - Survive until level 9. Extra mode in Gradius 3 - Survive until level 9. Extra Edit mode in Gradius 3 - Beat Gradius 3. Select Extra Mode to access more weapons. Gradius level in Gradius 3 - Intentionally get shot by the Final Boss Salamander level in Gradius 3 - Intentionally get shot by the Final Boss Stage select in Gradius 3 - Beat Gradius 3. Boss Rush mode in Gradius 4 - Beat Gradius 4 to unlock Boss Rush mode. Stage select in Gradius 4 - Beat Gradius 4. Stage select in Gradius Gaiden - Beat Gradius Gaiden on the Normal or higher difficulty setting.