My suggestion is to make an adventure game. That kind of game will probably need a lot of work, but I think you could adapt some of what you already have already done, for example, the images from 'Wet Night.'
Most of the game could be still pictures, with only the sex scenes animated. The puzzles could be based on responses to conversation.
Here is a rough example using 'Wet Night.'
Sandy (or Tania) picks up a hitch-hiker while driving to the others home. This would mean changing the first image to delete Tania from the car.
If all the images are from the player's point of view, not too many new images would be required.
Conversation in the car with different answer options follows. This would not require new images.
Depending on the conversation, player could be dropped off (game ends), or go to the house with Sandy.
Tania is at the house. There, the various options could lead to:
1. No sex, just watching Sandy and Tania
2. Sex with Sandy
3. Sex with Sandy and Tania
Because most of the game selections would be based on static images, with only the sex scenes animated, it should be possible to do this type of game.
If you're interested, I could help with the story.