I just finished Kazuya's route for this. It's a phone-based dating sim, a prequel to Hakuoki set 300 years earlier, but can be played as a stand alone game. It's set during the end of the Warring States/Sengoku period of Japan in the early 17th century.
The heroine, Yukina, is a ninja bodyguard to a demon princess, and chieftan of a demon clan in her own right. The princess has gathered the leaders of Japan's demons to ask them an important question, and Yukina finds herself drawn into human politics... and also drawn to one of the other demon chieftains.
The love interests. From left to right: Senkimaru, Kazuya, Chitose, Kazutake, and Shin

The (VERY SHORT) prologue is free but each love interest's route costs $5US. Apparently the routes share some content.
I just played through to the good end for Kazuya, a kuudere. It was great, but I'd rate the proportions as like:
Japanese historical drama: 50%
Anime-esque fantasy nonsense: 20%
Yukina kicking ass: 20%
Romance: 10%
All those parts are done moderately well, but if you're just there for the romance you'll be disappointed. From reviews I've read, the other routes are similar in this respect. Kazuya and Yukina develop a very sweet relationship, but it's more of a shonen-y warrior connection than romance for most for the game.
I didn't love it
quite as much as Hakuoki (WHICH I ADORE) but I still enjoyed it a lot, and it has some nice Hakuoki connections lore wise, eg the Princess the protagonist is guarding is an ancestor of Princess Sen.
Here's my reaction posts to the prologue and Kazuya's route