A hack and slash eroge with tearing clothes and a knight with a succubus curse, what's not to enjoy? Job of the Apprentice Succubus and Knight 2 does things right. Equal parts RPG and hentai game.

Per the game itself:

[Story]
The protagonist is going to a training academy to learn to be a knight.
However, she is caught in a predicament when they are suddenly attacked by orcs!

A fairy who happened to be there at the time shared some of its magic with her, 
and she managed to survive the situation.
Little did she know, that the fairy was actually--- a [succubus]!?

[If you share magic with a succubus... you know what's gonna happen right?]

Thus began the life of a succubus and a knight---


[Game System]
A hack and slash style RPG where you accept quests, 
make your way through dungeons, collect items, and more!
As your HP is lowered, your clothes gradually tear. 

- Difficulty Settings
Select from 3 difficulty settings: easy, normal, hard (can be changed at any point)

- Costume Variations
The costume changes not only the pose art, but is also reflected in the event CG

- Wording Change Functions
Lewd word customization capabilities. (testable in the trial version)

It's rare to see an eroge with real depth to it. Most of the time it's 'press x for sex', but then one comes along that would probably sell really well as a non-h game, and the sexy times are bonuses on an already good game. 

Sadly I don't know if there's an English translation, but context can help. I played Kamen Rider Battride War by context alone. Man I would Rider Kick for an English translation for those games, but I digress.