I LOVE IT! And I have some suggestion too.
I don't know whether other thinking like me or not.
But some times I think it's weird that the fox disappear but it has no gap or hole that the fox can hide. I think it will make more sense if you add some hole that only the fox can fit in it.
And it have one scene that you need to solve the puzzles in the basement and you got locked in it. And now I think the fox is evil. So it will make sense if the fox leave some note that say some thing like this "If you really want to meet me. You should solve this fist" And you should put some invisible wall in front of the door.
But the overview of this game is good. It's so challenging relaxing and burn my head some times too.
I hope you can understand my bad English.