It's a scene viewer of hentai animations. There's no gameplay. It's really great, tho.
I love the character! She's a maid, super attached to her master, but with a secret lust-demon side. I love the story's themes too, and even though it's light on story, there's just enough to set the stage for the erotic stuff, such that each scene contributes to the larger narrative as opposed to being random disjoint meaningless scenes.
It's animated programmatically (i.e. with like Live2D or something similar). Usually I don't like this kind of animation, I only tolerate them or merely find them okay. But here I love how everything looks, especially the little details in the expressions or gestures. Really, there's just excellent attention to detail. I like this more than most hand animated hentais.
The Steam download comes with a ~27 minute video file which is a compilation of everything from the game. I didn't play the actual game much, I think I prefer the video format. It's more portable, with a vertical resolution fit for a phone - so you can watch it on the train, at the office, in the courtroom, whereever. You could even watch it while lounging in bed, if you're some sort of freak. Also, the actual game doesn't actually appear to have a fullscreen mode (why???) so you need to use AutoHotKey or similar to go fullscreen. Tho the game's main menu does have some fun clickable animations, and of course if you want to loop sections or skip to certain sections, it's easier to do in the game compared to the video.
Oh ye and the voice acting and sound effects are mega excellent. Really important for something like this. Like, when she throws her arms and legs around her master, holding him into her as he cums, there's a super satisfying sound effect for it, adds a lot to the experience.