Addictive, simple gameplay
Lots of content
Great music
Nice aesthetic upgrade changes for cards and picks
Chests enable you to get premium content for free (if you spend your time unlocking them, of course)
Characters add even more collectibility
More mines add more variety
More mines add more variety
Weak points:
Graphics and animations are a bit boring
You end up getting a lot more chests than the keys needed to unlock them or you can have loads of keys but no chests
Missions can be frustrating
There is no message asking if you want to pay your premium cash (if you press the item accidentally it buys it for you)
You can only ask for artifacts through Facebook and not through Game Centre
You can only ask for artifacts through Facebook and not through Game Centre
Characters cost a lot of rubies