Hey Harshana,
Congrats on your first unity project.
Your greybox prototype which is the Truck, is really attractive. I noticed that you have considered about UIUX principles Building this game. I feel the Racing theme while playing this game much more because of the background music you have used.
For suggestions, I Think the buttons of the menu scene should be a bit bigger.
Good luck with your future projects!!
Hirushka Ekanayake.