Player Character has to answer the whims of a demanding female captor/Mistress, who relies on the PC to keep up-to-date with the latest trends in fashion. Said “trends” involve bringing the Mistress into the right bodyshape for a social event. For a simple game, this can alternate being top-heavy, bottom-heavy, or “motherly” (i.e. Belly-heavy). The catch is that the PC can only do this by increasing the Mistress’ weight between social gatherings.
Each time, the player has three options: increase the Mistress’ weight in accordance with the trends, or gamble on making the Mistress the new Trend Setter.
For example: if being top-heavy is “in” for the next gathering, the player can a) make the Mistress top-heavy, as she wishes, b) make the Mistress bottom-heavy or “motherly” to rebel against the trend.
There’s a 50-50 chance that rebelling against the trend makes the Mistress the new “trend setter”, which increases her trust in the PC, allowing the player to fatten her up even more for the next gathering.
If the gambit fails, the Mistress loses trust in the PC, causing her to gain less weight for the next event (and if she loses all trust in the PC, its game over). but if the gambit succeeds, the player can potentially combo several successful “trend setter” outcomes, and fatten up the Mistress to an enormous size.
Being a consistent “trend setter” also allows the Mistress more “leeway” to strike her own path - so, if she had been a “trend setter” enough times, the PC can just keep boosting one asset of her (her breasts, or belly, or butt).
This is important for the endgame: ultimately, the PC wants to get out of their service to the Mistress, which can only be done if the Mistress is no longer able to physically stop them.
There’s a set number of gatherings the PC must prepare the Mistress for (to prevent the gameplay loop stretching ad neauseam), and they must get her to a minimum weight that allows them to escape afterwards. That’s the basic, “Escape!” ending. Successfully comboing several “trend setting” events allows the PC to fatten up the Mistress even more, which can lead to four different other endings:
- the top-heavy ending, where the Mistress’ breasts had grown so large they anchor her to the ground
- the “motherly” ending, where its her belly that had grown so fat that it anchors her down
- the bottom-heavy ending, where she can no longer get up from her enormous ass
- the “victim of the trends” ending, a variant of the basic ending, where her whole body had been fattened up so much from trying to chase the trends that it completely immobilizes her
And, of course, there’s the “game over” ending, where the Mistress had lost all trust in the PC, and evaporates them.
The “trend setting gambit” mechanic can be tweaked: initially, its a 50-50 chance, but the more often the Mistress sets the trend, the more willing society is to excuse her for not following them, increasing the chances of her “rebellion against the trend” paying off for her and the PC.
Alternatively, the three trends could be like rock-paper-scissors, and only require a memorization from the player to decide whether or not they want to follow the trend or buck it. In that case, it could be like a real game of rock-paper-scissors, where the player would have to decide which of the three they want to pick each round. It would make it more of a luck-based game, unless you tweak it a little, and make it so that the same “asset” cannot be taken twice in a row, which would make it a 50-50 tossup between the other two “assets” in the next round. There could be a system of rewards or “boost” implemented that allows the PC to gleam which trend will be continued in the next gathering - the “safe” bet - and which could become the new trend. How these rewards would come about, I don’t know. But making it a luck based game is tried and true - look at “Don’t Fear the Jester” for a recent good example, but beyond fetish games, the ability to predict the correct next move is generally popular (Buckshot Roulette, Orange Roulette, etc.) as a mechanic.