You can't allow people to have an entire deck completely full of wishing coins, that's just ridiculous. If you're going to allow people to have full decks of rare coins, at least force them to be different ones, but even then it's an advantage that can replace all strategy.
It is nearly impossible to defeat a player who has unlocked the yellow cards, meaning the final discount on the cards. For some cards the influence of the 2 coin cost off is not a very major difference, but players very often will make a deck of cards which are ranging around 2-4 coin cost, combined with the discount they have a deck of cards which are now costing from 0 to 2 coins, I have seen many players purchase their entire bank of cards on their first turn. I understand the importance of creating a progressive experience for the players in allowing them to "upgrade" aspects of their gameplay and enjoy the experience myself, however the edge that is given in the second card discount is too sharp, and is leaving the game unbalance for more casual and newer online players.
I've played this game for over a week now, and while I have enjoyed it I feel I must state the following: Only Metris can defeat Metris unless you face a weak player; there is no way to defeat anyone with the third upgrade level of cards, who I assume have paid money.
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Hi funk! We removed the stamina bar, so I believe the game will give you a more higher chance of getting uncut dice from opening the chests! =D