I used test, that's surely a good thing. With test you can validate that nothing breaks immideatly, but it's still far from actual run with a car where shit starts to happen (At this point may be I'm playing it wrong and maybe you expected that user wont need to run car many times). But that's only my thoughts, you better know how your game should look <3
You are doing really well in my opinion for "pretty bad artist". You make it simple still recognizable and consistent, so it means that you have inner feeling that let's you do good ^^ thats cool! I don't have that (-_-'), even if i try making it simple, always looks like shit xD my wife saves me here :D