I heard it was great for a long time but didn't pay much attention because I'm not really into the cute anime at style and setting. I finally picked it up when it was cheap recently and found some of the best gameplay that I've seen in a while. Plenty of exploration, tight controls, well balanced difficulty, everything a great game needs.
The story and lore totally fit the cute anime style. You play a pet rabbit who woke up in human form. I think the main quest line is to find out why. There's a bunny lover's club that keeps trying to capture you. With the exception of a few enemies, every character is a girl and they're almost all wearing swimsuits for some reason. It's rather silly. I'm just here for the gameplay.
I don't know how long it is. I'm 20 hours in with 50% map completion.