I uploaded a playthrough to comments above as you are not the only one who requested this. I agree what you are saying about the camera and hitboxes. There is always room for improvement, but I decided this is good enough for now. Thanks for playing anyway :)
No, there is only one hitbox, but you die if you are hit 3 times in the same level. Shotgun enemies shoot three bullets, so they may kill you instantly. I understand why it maybe feel like it, because there is no visual indications for health.
I spent a week on this project and learned a lot from the feedback everyone gave me. I'm not going to update this game any longer, but I'll consider making a top-down game in the future so I can address all the issues this game had .