From the official website:
Furdiburb's background is constantly changing - no two scenes are exactly the same. The sun and the moon travel across the sky based on real-time. You can enjoy this casual game in leisurely fashion. Or if you're up to the challenge, you can take Furdiburb on an adventure! What happens when you tilt your phone? What happens when you drop fruit on the ground?
Furdiburb gets hungry and poops and is helpless to do anything about it. That's where you come in. But you get to choose - do you help take care of him or neglect him and laugh as he looks sad?