Also, it's pretty interesting you found it easy!!, maybe it was only the first part. The first half of the game is supossed to be actually pacific which is just gettin to the end of the level to get the instrument, but after you get the violin at the end of the level is when the gameplay really starts while you try to get back to the start now. At this point on each room waves of enemies try to destroy the instrument on your way back and it's supossed to be very hard actually, specially the boss at the end. Maybe you didn't notice this part because it's not too explicit.
Again, thank you a lot for playing my game and commenting!