Poor payout after buying coins
You get big payouts when playing from the initial free credit, but when you buy coins, the payout is really poor. Another big minus is that the game is promoted as offering free nights at Wynn hotel in Las Vegas. For this you have to collect minimum 1600 gems. One gem is collected once certain amount is wagered. It starts with 100k coins/gem, but once you get to level 34 (my case), one gem is collected every 2.2m coins. So I assume you need to wager much more for the 1600th gem. Useless to mention that you will probably never make it to the second night, unless you buy 1 billion coins which is the same (or even more) as buying a night at Wynns or Encore on booking.