Graphics are great! Music is nice (although i accidentally caught your bug)
Mechanics has a good idea, but i think you should give a lot of space (at least at the beginning to really show it's potential to the player) for training. Gameboy doesn't give mush resolution so i guess it'd be much better in bigger resolution. Speaking of that, camera smoothing doesn't really help with low resolution. Because when camera is slowly moving 1 pixel to catch up to player it doesn't look nice when pixels are this big (I'd have preferred fixed or player centered camera, as all genuine Gameboy games).
I love 2d Castlevanias, and of course i enjoyed your game! I admire your creativity, you just need more practice!
Best wishes!