It's a pleasant little game where you beat up Alucard to make a dialogue box with a cutesy anime avatar of him shout "ooww!". About as limited as you would expect a Castlevania game on the Gameboy to be, greatly enhanced by save states being a thing to avoid a game over when you lose all your lives. Enjoyable little Halloween distraction, not a Castlevania you'll especially remember but it's pretty solid in spite of its extreme simplicity.