This game is kind of good the complaint i have is the coins why dont we earn the coins ? Even if we didnt complete the challenge the earn coins should be rewarded no matter what we cant upgrade if we dont have coins how can i upgrade if i cant take the coins which i earn during the challenge they take it aways just because the challenge didnt complete ? So i have to wait for days to have enough coins to upgrade just beacuse i cant do inaap purchase beacuse i didnt earn ryt now? Any other option?