Pretty graphics and use of foreground elements. Some solid sound work, too. I also really enjoyed the world interaction like breaking pots and grass.
For your combat, I'd suggest introducing enemies one at a time to let players learn how to deal with them before mixing it up. More knockback (both self and other) would be nice, too, so I don't accidentally hurt myself after landing a hit (that's one of the reasons Hollow Knight has a smidge of knockback when you land a hit).
Having the camera raised so high makes platforming difficult because where I need to land is constantly out of view. I wish areas where falling meant death were better signified, as it's not always clear where's safe to fall and where's not. I would suggest teaching this without the enemy first, too, again so players have time to learn and get good.
The pixel jitter on the main character was bugging me. In Unity, you can usually fix this by switching the Rigidbody to interpolate, but I'm not sure how to go about it in Godot.
I gave up on the boss after dying twice. It was too difficult for my tastes and it felt too loose due to the lack of knockback and the fire rate. I probably would've kept trying if those two things were addressed, but because it didn't feel fair, it didn't feel like I was losing due to skill (even if I was).
That musical transition on the boss is a nifty touch of polish. Nice!