The viewport shows things outside the intended details. Like, I can see out of bounds, probably because I have a display bigger than intended?
I believe this can be solved by using a Camera2D and making sure that your stretch mode (Project Settings > Display > Window > Stretch > Mode) is set to either "canvas_items" or "viewport". I could be wrong though.
The game itself is fine, if a little basic. I like the wind breeze sounds when you're going fast, it sells the effect.