There are threads on this site full of games similar to it in this or that aspect, but sadly KP is peak degeneracy, everything else is a downgrade.
KP is amazing because it's
1. Battle fuck.
2. Tuned at a decent difficulty enough so that a reasonably good player that doesn't check a walkthrough will organically experience at least some lewdness (touching, kissing, bukkake, etc) before the end of the game, without having to lose on purpose.
3. There are mechanics for the "mental phase" with different lust meters for every body part, where you have to choose between combat buffs or reducing lust to avoid targeted battle fuck. The corruption is thus extremely gradual and it's possible to resist.
Plus, it has many amazing mini games.
It's surprising how many RPGm corruption games make the mistakes of too easy difficulty, battle gameplay completely unconnected from corruption and lewd stuff... Even without full battle fuck, the gameplay must contain at least be some interaction with the lust/corruption mechanics: lewd traps, status effects, or lust increasing attacks with cut-ins by the enemies, so the turn by turn combat is not a complete waste of time.