Really hits the roots of a metroidvania game. I got stuck where I couldn't open a door and I had to backtrack all the way back to the starting area where the double jump was needed. Then on it got better with more mechanics being added. Music matched with the way the player jumped where the entire body rotated was pretty cool.
An issue I ran into was the aiming where it didn't have full 360 rotation but fixed angles on where the bullet should go. The charged shot having some particle effects when hit and adding a knockback effect with some invincibility frames might make the game feel better. The art style which felt unique but also felt like something was missing or the areas felt a bit gloomy.
Overall the game was really good. You have built a really good core with mechanics that work well.