Hey friend, I'm loving this game! Nicely made.
Some pointers though, I like sequence breaking, but this kinda messes with the game in some ways:
Fyy: I played sectors 1 and 3 before finishing sector 2. Also explored sector 4 a bit
-I managed to get about 04 charging bonus things before getting the charge beam
-I feel I got the atomic power up way before I was supposed to. I got it in sector 3, by using the force field thing to be able to walk on lava without taking damage. Also, if you have that active, you don't take damage while on lava even if you don't have any ammo for it.
-I got the purple charge beam and immediately went back to the main hub, I was able to reach the Mark character (when he gets killed and you get the dash). I don't think I was supposed to be there, as I never learned he was the "????" (I'm guessing)
-After that I was able to just pass through that other area with the giant power plug thing, even though I never opened those barriers.
-Selecting your power up thing using L2 and R2 is pretty awkward as well, I feel I can never quite select what I want. Maybe try to think of some other option for that.
Other than that, I'm having a blast. Great game.
Also, you should consider creating a Reddit for your game, and maybe even posting it on r/metroidvania