I love it, so I'm typing this after two playtroughs.
The graphics simple, but cute, as promised. Also the music was nice. The main theme at the start menu remind me of Yoshii's. I loved it, so I love this theme. The ingame music wasn't intrusive, instead it was nice and decent. perfect for the background.
Now to the gameplay:
If you play active, like curious me, you don't need much time. I think it took me about one and a half hour for both playtroughs. Everthing explains for itself. But at some point, you will get the feeling, that something is off, that it's too easy. And then....well, play it it and you will see