It's not everyday that I stumble upon a game with such a rich Worldbuilding and engaging story and characters. Which is why I was left a little disappointed with how short it is (for now, at least). You made a great job of making me want more of those, so congrats.
If I had to say something I didn't like so much, is the contrast between the story progression and the sandbox sex scenes. See, the story advances even if you don't want to, you can't make the choice of where to go or when to sleep, it's very much Visual Novel style which in itself is all fine and works wonders (like in the other game, Casual Desires). However, the nights you spend with the succubus have much more meaningful approaches, since you can only do 4 actions per night and you need to grind experience and levels in order to unlock new positions. But you can't do that since your time is very limited. For players like me, that like to immerse themselves in the story and do things like they'd make sense for me, this means that spending each night doing a combination of foreplay, service, sex and spanking, switching around to experiment a little with anal, you end the game without having leveled a single one. Leveling progression is meant to be used with more sandbox gameplay, it doesn't work well with systems that limit your actions so much as this one does. Unless somehow unlocking new sex positions is going to be relevant for the story in any meaningful way, it doesn't make sense to hide them behind a level-wall like this. Well, it makes sense from the point of view that it's realistic, progressing towards more daring stuff as you keep doing lewd things, hence the "training" premise. But it doesn't make sense when you can't train effectively. Maybe this will be resolved as the story develops and more nights are added, but at the moment it feels unsatisfying. Personally, I'd change the limiter of actions per night to only account for number of times MC can cum, allowing for more free (and logical) use of the foreplay actions, as well as not end a night after only four spankings. Keeps it realistic, allows for some more meaningful choices (within the limited time constraints) and also gives the player more breathing room to experiment and immerse themselves on the action.
I'll be keeping an eye out for this one. It has potential, that's for sure. For now, it works better if you think of it as a Demo.