There's a lot of interesting mechanics here, especially for a visual novel. I've never been disappointed by the fact that being the good guy is the easier route in most games, but seeing a game that is trying to buck that trend is interesting. I do wish the principled option didn't predictably lead to a game over, because that does feel like a missed opportunity to have an alternate campaign where the twins have taken everything over and you lead a resistance. I understand that would be a good amount of work to do, though, so I don't blame you if you just don't want to do that.
I don't mind seeing the wife character sleeping with other people, and I would like Rowan to be able to sleep with other people as well, but I don't want them doing that without explicit permission from each other to open their relationship, for story immersion/roleplaying purposes. I'd like to have the option to see them give each other that permission very early on, ideally in the opening section of the game before everything kicks off.
Also, the death scene for the elder felt very rushed. It happened and then it was over, and it didn't seem to affect Rowan very much, I mean there's not even an option to discuss it with his wife. It just felt like it should have more impact outside of that one scene.
I don't know how much of this game I actually will play, because I really do not like playing the bad guy in games, but the idea of trying to remain good in a bad situation does sound reasonably compelling, so we'll see.