Screen size is really too little. On my wide screen it is a bit ridiculous, and plus I expect the view to be larger as we gain speed. Else it is just making the user drive blind and having to guess for the track, which isn't a very good idea.
The WASD command are a pain on azerty keyboard.
That's sad, I had interest in such a game, especialy that the car's physic seems good.
Could you add alternate arrows commands instead of WASD ? (or even ESDF commands, those are the same whatever the keyboard is)
Also, you should remove the "(c) Scirra 2011" on your last screenshot because as far as I know you and your game have nothing to do with Scirra company. You can put that you used Construct-Classic by Scirra, but the copyright symbol shouldn't appear.