Horror genre is one of the most profitable genres of games. The horror novel "The House on the Borderland" is public domain and is a perfect for a first person shooter game adaptation. In the novel, an old man moves into a cursed old mansion, explores the area around it, and finds that it is infested by half-pig-half-men who violently attack him and his dog. He fights back with a double-barrel shotgun. Throughout the following days, he secures and guards the house against an invasion of the pigmen. When he finally gets rid of them, he decides to descend into the underground river nearby and explore where the creatures came from. He eventually comes back up and experiences supernatural events that lead to insight into the universe. Full text is here.
I started work on this game, but this is a big project for one person and I'm looking for people to collaborate with. I'm using C++ and Lua and all custom-made open-source tools (Voxyc). I've already made one first person shooter game (Fateless) and therefore have the necessary experience to develop this. The first chapter can be free and we can charge for subsequent chapters in a freemium model. We can discuss revenue share. Please contact me if you are interested in collaborating.
The tiny hamlet of Kraighten
The ruins of the house, as found by Tonnison and Berreggno