I doubt you're taking suggestions or anything on this game at this point, given it's been over a month since you've updated it (not that that means much) but I really felt like the only thing that let the game down was the lack of any kind of personality from your oni.
I can't tell if she likes or dislikes the sex bits, she doesn't change her animations at lower health, she kind of blankly accepts everything that happens without any indications of how she's feeling. Moreover, you can't interact with her in any real way. When you feed her it's a split-second animation, and if you wait around she just walks about idly.
The game would go from a 7/10 to a 10/10 if there was just some kind of relationship progression instead of just the leveling up and fighting enemies.
Anyway, I bought, played and beat the game in about three hours or so. Great stuff!