Would STRONGLY recommend Magical Girl Luna. I also didn't have high expectations going in and the game blew me away. It's my favorite bondage game to this day, and that's coming from someone who doesn't like lolis (if you consider Luna a loli).
Worth noting the game starts rather slow and gets better and better. Everything from the end of the chapter 3 to the end of the game (which even includes an optional bad end dungeon) is pure gold to me.