This is super cute! Perfect for what it is, I love my lil mouse girl
I was literally just saying my next game is a desktop pet-like! May I ask what game engine you used/if any?
This is made in Godot, heavily using their powerful (albeit sometimes buggy) "Window" nodes!
I used this tutorial to get me started, it might be helpful for you too: https://github.com/geegaz/Multiple-Windows-tutorial