Good game! This game has a lot of things to say about it!

What did I like? 
- The background music. (Sounds awesome!)
- Game mechanics.
- Score.
What I didn't like?
- The main menu. (Looks so bad)
- Game UI in general. 
- The fonts.
- Thing is counting on the top. (I don't know what is it, I think it counts the speed of the car or something)
- Colour pallet.
- Normal colour, Highlighted colour, and so on of the buttons.
- Rules UI so bad.
Suggestions:
The main menu: 
- The text of the buttons use Text Mesh Pro, instead of the default text because, it is high quality than the default one.
- Choose one single font for the text of the two buttons. (Play, and Rules buttons)
- For the button component  for example use:
Normal colour: Yellow
Highlighted colour: Yellowish orange
Pressed colour: Orange
Disabled colour: leave it in the default colour
Then in navigation: Change the dropdown from automatic to none
Tip: Whenever you want to to choose the colour of the button component, start with a bright colour, then the others make them darker.
- Play and Rules buttons move them to the vertical centre.   
- The main menu, for the background, I suggest making the background just a solid colour.  Change the solid colour of the camera, and remove the current background from the main menu scene. Change the solid colour of the camera to dark grey, if used the colour that I said on the button component.
- Now in rules, use the same font for the texts that you used in the main menu, also don't forget to use Text Mesh Pro. 
- Move the text to the vertical centre, don't rotate the text like what you did, this was bad.
- I think the main menu is in the same scene as rules. If yes, you don't need to change the solid colour of the camera again.
- The rules texts change the colour to white.
- Instead main menu button, write "Back". Button component colours and navigation, change it to the same buttons of the main menu.   
- Now in-game view:
- If the thing that I said, in "What I didn't like?" is the speed of the car. To change the icon of it to something that tells me this is the speed of the car, or just write "Speed".  
- Game over, texts use the same font as the main menu. Main menu button uses the same colours as the main menu. 
- Your score, and congratulations font size make it smaller.  

I know I didn't write everything that you need to do, because the text will be too long!
I hope you found this helpful!
I think you are new to gamedev!
Great work! Keep making games, and never give up!

Destroying cars takes some skill, which made the gameplay quite exciting! Glad to see you added music to the game, too, because many submissions ignore audio completely.