Doujin Fever!! Train Assault!

Catching his girlfriend cheating is what starts it, but taking a different train home is what makes it worse: he runs into Hibiki, the sister of the man who wrecked his relationship, and decides she'll do as a target for everything he's still angry about.

What follows is revenge dressed up as seduction, tracked across repeated commutes rather than a single confrontation. The player works a train encounter into something more, then follows it off the platform into hotel rooms and other places where Hibiki has less control over what happens to her. Progress is managed rather than chosen freely, with routines to build and reactions to read before things escalate. It's a small, mean little loop, built around one grudge and one woman who happens to be standing in the blast radius of it.