The Wasteland Duel.

The Wasteland Duel is a short but highly replayable adult HTML game using the twine system. You play as a young witch, Martha, who is ambushed by the Witch of the Wasteland, who is intent on turning you into one of her bondage pets. Can you escape, and even turn the tables on the far more powerful witch?

The game contains around 10,000 words of content, mostly in the individual transformations you can inflict upon the witch as you wear down her magical defences. It has sexual themes, although few actual adult scenes.