I really like this game, the driving is smooth, the level design is great and the atmosphere of the game works really well with the style of game you are going for. For improvements I would say add more objects to the track like a tunnel or objects in the road as well as maybe some objects in the surrounding area to make it a little less plane. At some points of the game my car fell through the map if I went off the track, I suggest adding a collider around the track to stop this from happening. Overall, I believe this is a really good game and all the elements work well together.