Ok here's an incest patch that
should work even when the game is updated as long as nothing major changes. I guess I'm now one of those "evil modder" that adds incest to games.
There're 2 bugs that I know of in the current version (v0.22) of the game but they have nothing to do with the patch:
Install:
Extract and put the patch in Shelter-0.XX-win\game
DISCLAIMER: This patch is unofficial, I'm not related to anyone working on this game, I'm not even really a coder I just made the patch from what I've learned playing ren'py games and looking at their code and reading some threads on the F95 Programming, Development & Art board. It could probably be better but I tried my best.
Known Issue: For some reason at some point the dev stopped using all the different variables for the characters and just used their first name in the scene's code instead so you get the MC calling Angela by her name instead of mom, etc. I'll probably make another version later to fix those scenes but I think I'll wait after next version to see if anything breaks first.