Chests in Card Thief play a central role. Each game the player is task to steal a castles chest card and return it safely to the hideout. The chests hold valuable treasures which are needed to unlock new equipment cards and access the other castle decks. Early on we decided that stealing the chest card should be thematically and mechanically the goal of each game. If you reach the exit of the game without the chest your heist will fail. This introduces a few interesting elements.







Location

The first thing we designed is how chest will spawn. Our basic idea of how a medieval heist in a castle would work is that you enter the castle at a safe location. Then you would start to search for the chest having no or partial information about it’s location. Once found you would have to either return to your entry location or find an alternative way out.



We tried to integrate this basic gameplay flow in an abstract way into Card Thief. Since the game is quite linear in it’s level design we can’t really place the chest in interesting „locations“ where enemy or obstacle density is higher and the danger of getting caught would be higher as well. But since it’s a heist game we still wanted to have some kind of danger to stealing the chest. The first idea we had was hiding the card somewhere in the deck, which quite literary meant shuffling it in. We quickly realized that the chest could spawn as the first or the last card and that would break the „looking for the chest“ part. While still having the flow in mind we came up with the idea that most interesting location the chest could be in would be actually the middle of the deck. This way we can emulate the flow quite well because to find the chest the player would have to work through the first half of cards and to get out she would have to complete the second half as well. So the basic rule for hiding the card is „The chest card get’s dealt when 50% of the cards have been played“.



Value

The second aspect of the chest is it’s value. How do we decided what value the chest has? In the first iteration of this question Card Thief still had some sort of increasing difficulty system. Each successful game would raise the difficulty of a castle and with it the value of a chest. First game the chest would have a value of 1, than 2 than 3 and so on. At first this seems like a cool idea since we now have a good explanation of why the chest would increase in value since each run it would be guarded increasingly well. This introduced a nice dynamic of trying to get to a higher difficulty, but it turned out that this way of structuring each castle would involve a whole additional level of balancing and making sure each increase in difficulty would still be transparent to the player and also interesting to play. Unfortunately we couldn’t.



So we went back a step and thought about the increase of difficulty from a different angle. We then asked ourselves „What if the player could decide how much risk he want’s to take to get a higher value chest“. This question led us to the idea of a chest increasing their value each time the player would make a move. The basic rule is „Once a chest is spawned it’s value increases by 1 each time the player completes a turn“. Stealing a chest early means the player won’t get a very valuable chest but the chances she can steal it (because of the stealth needed to pick it up) and actually win the game become higher. On the opposite the longer the player waits the more difficult it will become to steal it while the reward increases as well. This way we can off load all the balancing to the player itself and create a whole batch of interesting decisions regarding chest values. Some equipment cards also work in conjunction with this mechanic and make play way more interesting.



Inventory

The third interesting part about stealing chest cards is that the player needs an empty inventory slot to actually pick it up. This means that if the player starts with 3 equipment cards, she is forced to remove one of her equipment cards since the inventory is full. The result are some really though decisions about how and when to use your equipment. Play it now or wait one or two more turns while risking that the chest value is actually to big to steal it.



The final chest mechanics fulfill several needs: Emulating a heist scenario where going in, finding and stealing the objective and actually escaping unseen are part of the gameplay. Having a really nice risk reward curve where the player has to do all the interesting decision when to pick up the objective and managing her limited inventory which can lead to an additional level of decisions.