Played this up to the first fight with the demons. (roughly 1hr of gameplay)
I'm a fan of sRPGs but this was quite a slog. I see on your game page you say you lowered the combat difficulty and trimmed the story, but I'm not sure either of those things worked in your advantage. Combat was too easy. I used one first aid kit in the 3 fights I did, and not because I needed to, just because I had a character with nothing to do and thought "well I have 25 of these, I guess I'll use one." The enemies were not aggressive at all, only ever moving forward if I stood in their range, and even then they would sometimes not engage. Speaking of range, why aren't guns ranged combat? lol
Combat lacked any sort of agency, couple that with the HUGE maps and it dragged on forever. Here's some changes that would really benefit things - make it easier to tell enemy and ally units apart, add a skip turn function, add a button that auto selects whatever characters haven't gone yet, and swap 'wait' and 'items' on the command menu, since you're going to be using wait a lot more than items.
I can't really comment much on the story, as it's not a setting I really care for and I'm pretty dumb when it comes to war politics and terminology, but I can comment on story telling. White text scrolling on a black background does not a compelling intro make, and here it was used even beyond the intro. What few scenes we got on a map were mostly stationary, even the whole demon reveal thing was very lacking and thus lacking in impact.
Maybe the setting with resonate with others more than it did with me.
Anyway, congrats on finishing your demo and uploading it!