A few observations:
- Camera shouldn't move up when the player jumps unless they are too close to the top of the screen.
- Player hitbox could be a little smaller, as you can "stand" on your tail at the edge of platforms with your feet on the air.
- I'm assuming the graphics are placeholders, but colors are a little bright and clash to much.
- In Castlevania the player stops walking when you attack adding a little bit of difficulty since you have to plan your movements better and choose if you are going to attack or move (Again, I'm assuming you are aiming for something similar to those games)
You have a really solid base to make a very good game. I'm already interested on what this will become. Do you have any specific goal or idea in mind? I would love to know. Good job!