Comments

Thats so cool lol!! I don't want to push any ideas on you, but maybe you could mix them together? Sort of like what DDLC did, but with the characters either falling into cultlike or religious delusions, causing them to feel the need for the themes you chose like sacrifice and divinity. 

You could setup the Visual Novel romance aspect to, with each character you pursue, you are introduced to a different part of the cult or something.

Just an idea, please ignore if you aren't feeling this sort of direction!!!

Also, for the game part, just in case you didn't know there is a really helpful software called Renpy that tons of Visual Novels are run on. It probably takes a bit of setup and tutorials, but for game development standards it is much easier to pick up than other software (from what I hear, atleast.) 

Take everything I say with a grain of salt, though. Plus, make sure to do your own research, because this is just what I've picked up from being on the internet a bit lol :)

Both your ideas sound genuinely cool and I for one have always loved visual novels and horror. I wish you luck on your project!!