Heart of the Woods is a fantasy yuri visual novel about a love between two girls that transcends life and death. · By Studio Élan
Is there a way to get the 18+ patch if the game was bought on Steam?
Yes, you can get it from Denpasoft here: https://denpasoft.com/products/heart-of-the-woods-18-dlc
Thanks! Another question: If I already started a game before installing the patch, will it still take effect when I load the save?
Yep, as long as you haven't already gotten to the adult scenes. They don't occur until closer to the end of the game.