what a fantastic game! im excited by the idea that this is a demo-- might there be more demons in future?
i only have a couple nitpicks; i wish there was something in the UI to display what the current items we are holding are! for all i know, you planned to but didnt have time :~) the second thing is that i wish there were more hints as to what the correct combination is to get the good ending. maybe im just missing them! one of them is made obvious by going through the dialogue with the girl, but the other is a little bit more of a random choice. actually i understood the hint with the mirror but it seemed a comparably unremarkable object so i never used it for the dismissal :( until i went to find out what it was supposed to be (side note- your code is very neat and pleasant to look through). i think you made a lot of red herrings, which is great for a game like this, but for that one im not sure what i was missing to know thats what i should have chosen
i love the art style- its simple, but in a very good way. visually, you have no choice but to focus on the demon, and i think that works in your favor. the music fit the tone, so you chose well on that. i really felt the urgency of the situation, and the dialogue felt heavy enough to draw me in. despite that i think the demon is just a cute guy, and felt a little bad to get rid of him. i really hope that youd consider making this an anthology of some kind! i would buy a set of exorcism missions :D