itch.io

That's a plot, not a kink.

As for kinks, I don't think any are particular to a prison game except for noncon, violence and rape (and no, accepting protection from someone in jail in exchange for sex is not consent). I guess bondage wouldn't make much sense (unless it's done by the guards) but BDSM can work, both in a physical and psychological sense. Most of the other kinks could be fitted (e.g. group sex, gangbangs, DP, watersports, fisting, interracial as a kink). You could probably have feminization even (obviously not transformative or cross-dressing but more as in treating someone as female and using female equivalents for their genitals, so more sissification I guess).

As for the plot, I assume there is a clear end in that you will have a limited time frame you stay in prison so it could simply be about surviving for that long. You can have routes depending on who gives you protection (different prisoners or possibly a guard) and then tie those to kinks. Or just have the option to choose no route and just try and stay sane (you could do a sanity subsystem where you eventually just shut down from the trauma as a bad end)