I've played through your game two times.
The first time, I forgot about the fact I can shoot enemies, because I don't really use ctrl in any game, so I got through the entire game as a pacifist by avoding enemies (and clipping through them on invincibility frames).
When I re-read your post and saw 'shooting enemies', I replayed the game. Honestly, not having the ability to fight back made the game more challenging and fun for me, although that's just my opinion.
Regarding the mini boss: on my second try (so when I didn't clip through the mini-boss), the fight with it was indeed quite fun and the best part of the game. Although, in the last phase of the fight (when it starts shooting a large projectile downwards and smaller on the sides), I've just stood in place between the hitbox of the large projectile and the area where smaller ones can spawn. Nothing has hit me during the last phase when I stood there, so I just shot upwards until I destroyed the mini-boss.
Regarding the story: there's only one dialogue I could find - the one at the end of the game. It was understandable, if that's what you're asking about. If you want an opinion of its quality, then I can't give it, because there was not enough story-content to rate it in any meaningful way.
Other: I think it'd be better if the player stuck to walls automatically instead of having to hold X, or at least if "hold x" was replaced with "toggle by pressing X". Trying to navigate the controls was harder than I feel it should be, and I think that manually holding wall-climb was the main reason of it.
I haven't noticed any bugs.
Good job overall.