Pretty neat mining game. Couple things 1. In game purchases wasn't received and the restore purchase button doesn't work . 2. In game boosts you pay with gems that have a time limit, say 5 min boost , ends the minute click an ad or try to stack a boost with another boost. You just lose it and get none odnthe gains for missing time . 3. At no time can you earn 100 gems on a day without buy them . In game upgrade requires gems and upgrade price gets increasingly difficult to attain as you lvl