To hard to unlock more levels

I really like this game for the graphics and gameplay. Overall its fun..BUT to unlock more levels is extremely hard I cant get into the top 10 the times are near impossible to beat. Can you please change the way to unlock the levels?? As of now my gameplay is limited and even though it was only $0.99 I feel cheated that I cant play the whole game!!!

Sissybissy12 about Nano Rally