I liked the retro look and play. I had some issues with transitions between the rooms a couple times. The player character got lost and didn't show up on the screen and had to restart. Another similar thing happened when I climbed a ladder and fell right as the transition happened to the next room.
The music loop is a little too short and can quickly get annoying. I do like that you've added an interface to control the volume, so that helps. :) I think if you had a longer piece of music, it would improve the audio experience.
I liked the derived sprites from the Castlevania games. Loved playing many of them and the character's movements felt at home here. I would have liked to see more of a beginning level, but with time constraints, it's completely understandable.
It's a great start! Would love to see more in the future.