having taken the time to cool my head a bit and step away, get a more objective view the game as a whole (not fully objectively obv, this is still pretty biased hahaha) i think the concept is pretty professionally executed, i do think the ai parts of this are holding you back.
if this was made with "crappier" art and sound i would have found this charming, the merging upgrade system is a unique idea (in need of more explanation to the player), and the rythm shooter is an interesting design space (tho i find not really having direct control of the gun encouraged me into a boring play pattern of ignoring the actual game to just focus on the merging aspects). The art doesn't actually convey much of the information of your story to me, it's just noisy wideshots of planets on a screen too small to see see anything, and the songs feel very hollow (cosmic mush in particular's lyrics feel so on the nose i think i genuinely let out a chuckle on stream because of it, which took me out of the experience). Your aestetic choice of beige background/primary colour scheme i actually think is pretty inspired, tho you should experiment with colour pallet options to see what clicks with players most, something with higher contrast may get across the higher stakes and horror themes more (black or navy blue primary colour like DOS box? i know it's over done but they do it cause it looks sick), as it stands i think this is a good design choice that fights the rest of your other good design choices.
And that's really the long and short of it, the game feels like it's fighting itself and as a result feels kinda hollow, there's something interesting here to refine, but if it were me i'd find a musician and artist to fill in those blanks, cause the stuff there now detracts from the whole (and is devisive so you're gonna get more biased dicks like me flaming it just for it's inclusion). With substance the music and art will really shine in the framework you're building here for it. As it stands i'm put in a hostile position playing it, i'm predisposed to be more critical of your work, and engage with it less. and for godsake pull the camera in, use your deadspace i can barely see what's happening :p