@higi, did you install java 8 like the first post mentioned? if so, then double click on the jar file in the unzipped folder.
@ataraxia, strange, it looks like it would work... was there any errors in the logs?
@mars, yup as dndw says, there's a lot of missing scenes. Sorry about that.
@ases, thanks for the comments. like I said, this is all pretty tentative, and may change. I think the main character will be end up being a girl for sure right now, at least in the story I was envisioning. Was wondering if I was going to add a forced tg option. It'll just be flavor backstory anyways, so it probably wont matter.
@red, the plan right now is for the mc to have a slow transformation into a half/full demon through the course of the game. In addition to that, you will have many NPCs across the town to transform into monster girls, kind of like village of nightmares if you've played that. Every target you corrupt will end up as a monster girl of some kind (whether or not they start off as a guy). The corruption of side characters wont be COMPLETELY necessary in the plot, but will help you a lot and is the majority of the side quests.
Anyways, I know the setting/fetishes wont please everyone, but it's just something I wanted to do. There's plenty of other games out there catering to specific needs