Copyright laws are ugly, but what makes this situation even weirder is the basis of the work being copied and recreated (incest rape porn) and the jurisdictions involved. People are spread all over the world, and while most countries follow the same basic principles in Intellectual Property (IP) law, there are some differences from country to country.
That being said, there are ways to protect oneself from blatant infringement. Sidenote, I am not a lawyer, but am a legal geek.
Since this game is a computer game, it consists of multiple pieces of media such as code, graphics, video, and sound. Modifying those pieces to be different from the original usually has been enough in the past to prevent infringement. The basic rule of thumb has been 10%. That can be accomplished pretty easy with a game like BBS. Correcting all of the typos in the text alone would probably account for 10% of the story changes. Going through the code and cleaning it up, or changing things like the hint system or UI would also count towards that total. If we're looking at recreating the renders instead of straight up copying them, then we should be safe. Maybe even using different porn clips in the Liza Computer Corruption sequence could work. We haven't gotten to adding new features or characters yet.
The only way that I could ever see it being viable for RA to pursue legal action against a team of pirates remaking his game is if this group is so successful and makes a metric assload of money on this venture. Even then, who would want to put their real name on a legal document saying that they created the Incest Rape Porn that served as the inspiration for this group to work. He's not Marvin Gaye's family and we're not Robin Thicke and Pharrell. At that point the fastest way to solve that problem is bring him into the fold and share the wealth to shut him up. But that's assuming a crazy scenario that isn't likely to happen.
