Anthony T. Goh, Software Developer.

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Deck-Builders: Game Theory (Part 2)

Part 2

Last week On F-Quad … 


Seriously, if you haven’t yet click the above image and get yourself a copy of this game. No promotional stunt, just a good game.

Wait. No. Not a serialized TV Drama here.

However … Last week we discussed some of the concepts in brief behind why Deck-Builders are such a powerful and fun genre. Specifically the Decision-Sequencing-Reward loop that drives people forward. This week we’ll talk a bit about the specifics within the Deck-Building genre that allow a player to strive for excellence.

Next week we’ll go into some interesting UX and design choices that that Monster Train did to further some of these goals.If you haven’t read last week’s yet, you probably should. It gives an overview of Monster Train, and four important concepts: Decision Matrix, Sequencing, Reward Loop, and Variance. 

If you’ve done your homework and you’re ready to move on, then let's dive a bit more into the mechanics of Deck-Builders and what they entail with the above concepts.


(Lack of) Control of Variance

As discussed last week, Variance is the most important aspect of Deck-Builders. Randomness in a programmed way, a way you can expect and know a bit of what the next randomness is going to be is important. Deck-Builders most often accomplish this in two ways: First you are building a deck, and when you run out of cards in that deck you shuffle all your used cards back into a new deck. This is of course a random order and you are never quite sure what order you are going to draw them in. 

Second, Deck-Builders don’t always give you the same cards to build with. You don’t always have access to every card. Sometimes it’s drastic - Seasons for instance has hundreds of cards and even in a four player game you’ll barely see two or three dozen of them.  Most of the time however all the options are on the table - just which one comes up when is what is variant, if they even come up at all.

Monster Train of course has the deck that is recycled every time you draw through it. It also provides you with card ‘packs’ at the end of every battle where you can choose one of three cards for each pack to add to your deck. In addition special encounters and checkpoints in the journey down the rails you can pick up additional, special cards.

There are two other levels of variance as well. One, upgrades to cards and special abilities (called Relics) are somewhat random. Second, there is a bit of randomness to what enemies will appear each round of a battle - while you have an idea it is not the same every run - furthermore, the final boss has a different ability each run, causing another thing that has to be planned for after the game starts.

It is important to note however that Variance should be somewhat within the players control. The player can’t control what cards they get, but they can control when they get those cards (or to skip them!) There is no randomness in the damage the enemies will do, meaning there is no losing the game due to a bad roll. This is bad variance!  Losing to something beyond the player's control leaves a bad taste. Losing because of a bad decision made by the player however, that is just a learning experience. It could have gone better, so it is not the games fault but the players. The outcomes of a round are completely within the control of the player… even if many of those outcomes are not very desirable. 

Monster Train has two abilities to help relieve these pressures from drawing (and tie into Velocity below). Holdover and Permafrost. Holdover keeps a card coming back every time you cast it. This means you can continue to use a (possibly important) card every turn. Permafrost is kind of the opposite - a card with Permafrost becomes Frozen at the end of your turn, and stays in your hand until you cast it. Both of these can help reduce the randomness associated with a deck of cards.

Synergy (Combo’ing and Looping)

I don’t know what this is either, but maybe it works out for some kind of … building … example? Gah Marketing where do you come up with these ideas!

The next concept that needs to be studied in Deck-Builders is that of Synergy - or Combos and Loops.  Synergy is any two cards or abilities that work together to create some sort of favorable outcome for your play. Building up the synergy of a deck is one of the more important concepts to follow. 

Most often synergy comes by the way of combos. A unit has a special ability and so you make that ability work better with a spell. Or you add a second ability that is more effective with the first one already there. 

Loops are a bit more complicated, and often far more difficult to pull off. They require culling the deck to a point where it basically continues indefinitely, looping through the available cards to some effect. You continue to play cards gaining something - a resource, a buff, a debuff, or damage until you are satisfied with the amount and then you stop. This is also referred to as an infinite loop. (To get more into this we’ll need to talk about Velocity in the next section)

Monster Train does this beautifully. One of the most important aspects about picking Synergistic combinations of cards is at the start of the game - where you pick two clans. One contains your champion, the other provides support cards. Because each clan in Monster Train has different abilities and a different play-style, the choice of which two clans you take changes what synergy you will be looking for.

Furthermore, the clans theme and special abilities all have synergy within themselves. Take the Melting Remnant - They have an ability called Burnout. Burnout ticks down each round and when it's gone the unit dies. Of course this means that many of their units with Burnout are more powerful than a similar unit from another clan. It also opens the door for many synergies, such as providing more Burnout to a unit so it stays around longer. Bringing units back from the dead. Or units who grow stronger when another unit dies. These are all different strategies off just a single special ability, and there are four clans each with several different play-styles among them.

Velocity

The concept of Velocity is not a difficult one to grasp - it is how fast you move through your deck to find the combos needed. A very high Velocity of your deck is how you can reach infinite loops. It is however a difficult concept to follow. Every Deck-Builder is based around the core concept of gaining new cards. However, you only draw so many cards a turn. So the more cards you have in your deck, the less likely it is you will see the cards you need at the right time - and your Velocity is lower. It is very hard to resist the nifty new card that is right there, and that’s what makes the idea of Velocity hard to follow.

So, all successful Deck-Builders have some sort of “Remove” card mechanic. In Monster Train every shop has the option to remove cards from your deck. There are special points where you can remove two cards when you reach them during your journey. And some cards have the Purge keyword - meaning they are played once and then gone forever.

This also provides a very interesting enemy ability. Most often seen in digital versions of Deck-Builders (because it is just easier to do than in a physical one) enemies can sometimes add cards to your deck - dead-weights that do nothing (or worse, actively hurt you!) and those slow down the velocity of your deck. 

Remember those two abilities, Holdover and Permafrost? They also affect Velocity. Holdover certainly helps reduce the random factor of a deck, but it drastically slows down the velocity. In effect, every turn that card is used it reduces the draw of the next turn by one. Permafrost however, while it may not make a card as reliable for every situation, it actually speeds up the velocity of your deck. By removing itself from your draw pile until you cast it you have less cards you have to go through to find the other parts of any combos you need.  Consume helps as well in this regard, for the same reason.

Scaling

The next major concept to take into account with Deck-Building games is Scaling. Scaling is loosely defined as “How does this card change and continue to be useful as the game state develops.”  

Now, many versions of these games don’t have any form of scaling at all - Ascension (in its base form, expansions may have something) doesn't, for instance. It is often more of a digital concept because remembering what cards have what effects added to them is difficult in the physical space. It also requires there to be a reason for cards to scale. In Monster Train the enemies you fight get bigger and more dangerous as the journey goes on, and so cards that were fine against the little guys at the beginning will not fare so well unless they can scale.

This aspect needs a mechanic to either buff or upgrade other cards. Monster Train allows all the cards to receive upgrades as the game goes on, bought from shops and applied to one specific card at a time. These upgrades are often synergistic in nature, and a better synergy means a better scaling. Adding more health to a unit allows it to survive that initial attack by the bigger enemies later in the game.  Adding more damage to a unit that attacks multiple times makes it an even bigger threat. It however needs to be limited so that while the player feels like they are getting more powerful, they aren’t getting too powerful. A hard line to walk.

This is where Scaling becomes a very difficult place for a player. The limited factor of such means that sometimes it can be a trap to upgrade certain units. Other units which seem really strong don’t scale well and are perhaps not the best choice to take. Learning to evaluate these is difficult, and is a process that also requires learning the flow of the game and how such things will come about in later stages.

Precision

Finally we have Precision. This last strategic principle is the most important. Where you need Velocity to get through your deck and Scaling to make sure your deck can still handle what comes against it, neither of those matter if it is all over the place. Combos and Synergy works great but if you try to do too many different combos, the pieces never (or at least rarely) fall into place at the right times.

Precision is a player choice thing and not dependent on any game. It relies on picking a strategy and sticking to it. It also relies on understanding the Velocity of your deck. If you have a high velocity, you can get away with fewer cards that do the same thing - do you need 2 cards that bring units back from the dead if you can cycle through your deck every couple of rounds? 

They say puzzles are good for your mental health. I prefer mine to be a bit more interactive and on a shorter turn around.

All together now

All of these things have to be taken into account when thinking about the strategy of a Deck-Builder. Purging unwanted, weak, or bad scaling cards from your deck. Keeping it tight and lean so it has a high velocity and a single point of attack and executing that synergy over and over again. Being able to do all of this while uncertain of the exact nature of what you will next be able to make changes to your deck or with what you will face. Finding the right strategy while working around those variances is what makes it an exciting puzzle to solve  - and the reason that Decision-Sequence-Reward loop is very successful.


Next week On …

Now we’ve had a nice bit of talky about the cognitive and mechanical aspects of Deck-Builders and what makes them interesting and how to use that to play better. Next week we’ll go into more detail with Monster Train, on a few aspects that have impressed me quite a bit.