Yōkai Yashiki

Yōkai Yashiki is what can best be described as an early Metroidvania game. You play as a boy armed with only a flashlight venturing into a ghost manor to find his sister. The flashlight shoots out projectiles that kill monsters. Its battery is both your attack power and your health. The game has 5 maze-like stages that can be traveled to without beating the stage bosses and backtracked.