Monster Lair

Wonder Boy III: Monster Lair is a hybrid title that combines platforming action with horizontal shooter segments. The player controls a character named Leo, who fights against invaders threatening the land.

Gameplay alternates between two distinct modes. In the platforming sections, Leo's vitality gradually depletes and must be restored by collecting fruit. Various temporary weapons can be acquired, which also replenish health. The game transitions to shooter sequences where Leo rides a pink creature; here, vitality only decreases upon enemy contact. Boss encounters conclude each stage, with some requiring a two-phase defeat and a color change indicating damage taken.

The game supports two-player co-op, allowing a second player to control Wonder Girl. Losing a life occurs if vitality is fully depleted in either type of scene.