This is a great VN, but 1 thing I'd find odd and it's how the MC uses "by the eye" or "by the void", in lue of "oh my god" or "goddammit*. This is to say he uses the idioms of, to lack of better phrasing, the aliens and doesn't use the ones he grew up with. I do get it, you want to use your form of language but it does take away from the MC's own humanity and history to just discard everything and use a way of speaking that's completely foreign to him. It would make much more sense for him to keep using the human language and his old way of speaking, especially since at least to him he's the last human and actually holds on to it very hard.