Deck Size: Your deck can have a minimum of 30 cards and a maximum of 60 cards.
Card Duplicates: Your deck can have a maximum of 6 cards of the same type (does not apply to pillars or pendulums).
Hand Size: At the beginning of your turn you draw 1 card. You may have no more than 8 cards in your hand at any given time. If you have 8 cards in your hand at the end of your turn, you will be forced to discard 1 of them.
Equipment & Creature Limits: You may have no more than 1 type of shield in your shield slot, 1 weapon in your weapon slot, and 23 creatures in play at any given time.
Activated Abilities: Some creatures and permanents have activated abilities, whose activation costs are listed by their description. These abilities can only be used once per turn unless otherwise specified. No activated ability may be used on the same turn that the creature/permanent carrying it is brought into play. (Note that a newly mutated creature does not suffer this restriction.)
Win Conditions: You win a game either when:
Your opponent's HP are reduced to zero or.
When he must draw a card but is unable to do so.
Rewards: Winning a game will grant you "spins". Every spin gives you a chance to win a card from the deck you played against (beside pillars, although a current bug makes it possible to win pillars anyway). This also means that winning against a highly specialized deck will give you much higher chances to win cards.
Card Rarity: Different cards have different degrees of rarity; rare cards are more expensive, and extremely rare cards are just not for sale.
Cheating: Exploiting a bug that gives infinite money/cards/wins may result in your account being deleted. Nothing against you, you found a bug and you are having fun with it, but it is just not fair for other players.