THE WORST. There's no way you can progress without either replaying levels continuously till you level up (every level gives you around a 100 xp, for leveling up you might need around 5000-6000xp, you can calculate for yourself how much you need to replay the levels to level up) after which you get around 6-7 gems. And that's it. The Casino is a scam. You play it 20-30 times and all you get is 150-250 coins. What a joke.