I think that there's no variety in the cars in the garage and I could afford them all after 1 race. The game is only available in single player and you can't even race the cpu. And, when you make a track and try to come back after racing on a different track its disappeared from 'my tracks'. Is good for younger kids though.
My 4 year old loves this but is restricted in his ability to build a decent track because it won't let us sign in. We've tried loads of times with loads of combos and it just tells us that the combos not right or is already used which of course we know cos it's our effin details. Iv noticed from other reviews that this has been a problem for over a year now which not only have the developers not addressed but don't even have the decency to answer the complaint. If you want the thrills and spills of driving on a basic track then annoy your child by trying to explain to them that the developers have zero respect for their customers this is for you.
It is a good idea for a app but the only problem is the fact it glitches so much u can't really play on it, (the app has once glitches out my kindle so much it malfunctions.) If you want my advice do not get but this could be a very successful App.