Good luck! To be honest on the discord server some other people were asking about how far is *too far*, so I just wanna preface this if you ever do feel like making the dark/cult game :p If you think it's bordering the NSFW line, then just add a warning at the start of your game and/or on the itch page, as it helps a ton with moderation and just making sure everyone has the best experience.
For example it's quite hard to have a theme like sacrifice as a Halloween story mechanic, without having a lil' bit of blood here and there haha, as long as you just make it clear what's gonna be in the game then it's fine. Same applies for anything religious that could potentially be offensive or anything, so if you're not sure if it's too much or not, just to be safe I'd put a warning somewhere.
Anywho, that was a bit of a rant sorry. Super excited to see what you make and have fun!