I like the game but I believe you should ramp up the difficulty just a tiny bit. And maybe a more elaborate updrading system. like for example instead of just pressing the plus button have separate menus that you can upgrade and buy specific parts (ex colder sparkplugs and wires, bigger carbs, headers, exhaust, different types of tires, maybe like different car support rails and cages for strength category, differnt spoilers, under car slick panels and diffsuers) just ideas. Just a tad of depth and a few other little things could keep people engaged.
 "American Racing"){kind=icon}
 "Viricide"){kind=icon}