Recommend me some japanese PSN games

I heard from a lot of people that the japanese PSN has a lot good free stuff on it and since I just recently realised how easy it is to access the jpn store, I’d like to try it out for myself. Basically, recommend anything you think is worth playing and is free. Also, please try to include some instructions on how to find it exactly. I’m having trouble navigating the store.

And on another note, the Catherine demo there was removed a few weeks after it was released, but they restored it soon after the release of the game in Japan. Is that true? Because I can’t find it. Thanks in advance.