I have to agree with one previous comment that the server must be running on someone's old iPhone. Terribly slow and constant crashes. Way too many long ads, and many times the rewards for these ads are not given after sitting through 30 seconds of garbage. Upgrade your servers, or get out of the game! And don't bother sending me a we're so sorry reply. Update: Typical! I just posted this review and while I posted this, I returned to the play screen, it crashed and I lost the challenge rewards!