Firstly, absolutely love what's here so far. Dialogue is entertaining enough but isn't the main reason i'm playing so it doesn't need to be grandiose or anything like that. It serves its purpose well.
That aside, the only things I could want are breast growth (Which i did read that the body type work is awful, but honestly even if it was only visible nude I wouldn't mind. Super compression clothes moment lol) and just more burps. And i mean both in variety and frequency.
If you do add the ability to burp more often or deeper/longer I think it would be awesome if it had sliders but if you'd rather it have gameplay implications you could always add things like soda to the food pool, bloats more and all that jazz.
That said, I do agree with Mushin, the facial expressions are FANTASTIC and I could only ask for good expressions on loud/deep belches. With that in mind, a minigame where you could rub the MC's belly would also be a neat touch.
Keep up the great work, I will be watching with much interest ;p