It is possible to collect the same card multiple times. But don't you worry, duplicates are not worthless: If you get a card you already have, it will be turned into shells according to its rarity.
You can see how many shells you have at the top of the house's room overview.
Once that bar is full, you can choose one out of 3 different rewards!
You can see how many shells you have at the top of the house's room overview.
Once that bar is full, you can choose one out of 3 different rewards!