Trial/PV available at the author's ci-en (http://ci-en.jp/creator/2024/article) or DLSite (http://www.dlsite.com/maniax/announce/=/product_id/RJ237295.html).
There's an option to skip the intro and I don't speak JP so I have no idea what's the story. Just seems like this succubus shows up out of nowhere and chose to feed on the MC. The goal seems to be to feed the girl a certain amount by a deadline.
You've got three bars: hunger, sleep, and stamina. Stamina's used in having sex with the succubus: the amount of stamina you burn is how much you feed the girl. During sex, you can switch between speeds or positions, There's an option to also freeze your stamina if you just wanted to watch the animations. If your stamina drops past 0, you get a game over. You manage all three through items or sleeping. You can go out into town and go to shops to buy various items, although there's a quick-travel by hitting X in town. There's a day and night system, so certain things are available are certain times.
There's a restaurant mini-game as a part time job, which can only be done in the morning I think. Each round of the mini-game involves four people ordering dishes, and you memorizing the dish, the person # who ordered it, and the location (Left/Right side) that the customer was at. It's uh, pretty tough for me.