Have you thought about doing things like Kagura Games? They release the base game with no 18+ sex content but then have a patch that is released for free on a different website (they release the patches for free on their own website for if you purchase the games from steam) to get the full experience. This might be the best way to dodge the payment card censorship. This way the only thing being 'purchased' is the fighting game part of it. It should be like having your cake and eating it too. I love this game and I really want to see this game completed.