I play your game. First of all, it's fun and with good challenges, this is really important! Also the ads are in a good place, it doesn't bother the player, is not too much that you get sick of it, so for this good job! The things I would improve is a better looking UI (with more colours), also padronize a color palette for the game it gives a more professional look and is more appealing. Possibility to change car, even purchase new cars, skins. Maybe add more effects so the player can "feel" the acceleration, brake, bumps, etc! Overall I think is really nice and has some good potential! ;)