Cards level up

• Each card can be upgraded a certain amount of times.

• Upgrading increases the effect of cards and sometimes even adds a new one.

• To upgrade a card a player needs: - SC; - card currency (non-crypto - is acquired by finding duplicates of cards in boosters).

• The price of the upgrade depends on: - the current level of the card - higher level = higher price; - the rarity of the card - higher rarity = higher price.