Gameplay-wise it's looking rock-solid, though the boss seems to be on a bit unpredictable side later on. Good work so far.

Really fun and promising. You nailed perfectly how NES Castlevanias.feel.
So far the only issue I found was that sometimes enemies can knock you back through the walls, and out of the level, forcing you to restart the game. Happened to me 3 times at the boss battle, and once in the room with lots of bats.
As you can imagine already, I'm loving this game and hope to see more progress on it. Great job!