I personally think that movement in games is a deceptively difficult task to achieve. There's a lot of work that goes into games like Celeste/Mario to make the platforming & movement feel just right. One quick suggestion would be to increase the amount of jumps you can make to N and divide each jump's height by N to make it feel less disorienting. There's many ways to approach the player's kinematics, one way could be to set an initial velocity the moment the left/right input was made and then ramp up to the max speed. This makes it easier to go from {standing next to a ledge you want to jump to} -> {press jump & left around the same time} -> {make it to the ledge}. Then you can make it such that a running start is required for more advanced jumps.
Then movement gets super complicated when you add more bonuses to make it super accessible yet super fun https://twitter.com/MattThorson/status/1238338574220546049?s=20 (example from devs behind Celeste).
Whenever I shoot my gun the camera shakes a little bit and it made me feel super disoriented when I tried to shoot while moving. I learned about Cinemachine during this jam and you might want to check it out to make it easy to do cool camera stuff in Unity https://www.youtube.com/watch?v=Ml8ptNeezsU&ab_channel=CodeMonkey.
I think your premise for the balancing power/health is interesting but I couldn't really figure it out. I got to the final boss but couldn't beat the final boss.
Regardless, movement/camera design and combat balance/design are skills that you hone overtime. I really enjoyed the game for what it is and you should be proud for making something real cool within such a short amount of time. Not everything we have in mind turns out the way you want to, but over time you build instincts for what might or might not work. Keep it up!