Nice! Always good to see new developments from you! As for the secret ending... I haven't played the game yet, but I'll take you up on the challenge of finding it when I do >:)
Update: I am perplexed. I must have played through the game at least six times, and I just can't figure out what the secret could be! Also, not sure if there's supposed to be audio. Noticed there's an audio slider in the menu, but I didn't hear a single sound at any point in the game, even during the spanking from the aunt. Tried all the different audio drivers in the winsetup file, but it made no difference. As for the second spanking which I believe to be the aforementioned secret, I noticed a few things which MAY be related to it. If you click the couch beside mom and interact with it at all, it says "I have a bad feeling about this", and there's a random unused plant to the right of the aunt's house, which gives the message "It's the second largest flowerpot I have seen today." upon inspecting it. Not sure how the flowerpot may be related, but I also haven't found a use for the (red herring) seeds, gardening manual, or hairbrush in the room. Not to mention the "stuff dad left" on the desk in Gem's room, which almost certainly has some unknown purpose.
Overall, very intriguing game! I love what I see so far, and I WILL continue attempting to find this secret ending. Thank you for taking the time to make this! <3