I believe the entire game is just that, unlike what other comments have tried to guess, I was curious and decompiled the code (for educational purposes only, ofc don't be like me :P), the freezing is intentional (by godot's terms, it's a "get_tree().paused = true") :D, I think originally the concept of having beetles to attack the mushroom to decrease its health is quite interesting... sadly I think the developer does not have time to implement that feature.
I really love the parallax and what the game could be! Good job!