KatFS Alpha: The New Balance Philosophy

Hello all! I'm breaking the monthly general devlog pattern for my game, Kalia and the Fire Staff, for a topic that warranted a more in-depth analysis. For those that may be unfamiliar with the project's development, Kalia and the Fire Staff (which I usually refer as KatFS) is a game where the player has access to all sorts of fire magic, set in an environment chock full of stuff for them to burn. Not only can the player create fires, but they can also spread on their own and turn any encounter into infernal chaos. It's best showcased with a screenshot:

Ok, introduction out of the way, onto the topic of this devlog. 

THE CATALYST

Recently, a new mechanic has been in planning and development which will allow the player to drain energy from fires in the level, refunding some mana back. The primary intention behind this mechanic was to provide the player with a way to directly extinguish the fires they create, but I figured it would also be interesting to include the mana restoration aspect to make it generally more interesting to use. As a reference, think of the InFamous games, where the player can restore their powers by draining electricity and other elements from the environment.

However, with a new feature comes new potential balancing issues. The big one being, how to keep this feature relevant while also not having it overshadow other mana restoring methods? Since the player can create fires almost anywhere, they could easily have access to near-unlimited mana restoration at any point in the game if this feature is not balanced properly.

Ultimately, a choice was made: the mana gain from draining a fire should always correspond to a fraction of the mana cost required to ignite it in the first place. This prevents the player from leeching off a single object for infinite mana restoration while still allowing for more clever plays by taking advantage of the fire spread to multiply their "investment" and come out with a gain. Or at least it encourages "cleaning up" after a fight to get a head start on the mana pool for the next.

However there lies the next big balance question - how should the expected mana cost to ignite a given object be determined? And that question has led to a major breakthrough in how the game oughta be balanced going forward.

HOW IT USED TO BE

Thus far, KatFS has lacked a cohesive "balance philosophy" behind it as a whole, with the focus rather being on individual objects and how they compare with each other. Zombies are slow, dumb and very flammable, but also beefy; compare with the skeletons who are nimbler and fire-resistant, but more brittle. While there has been an attempt to differentiate flammable objects in their characteristics, they've been behaving similarly for the most part, with only slight differences in their properties. It worked for a prototype, but always left a concern that the fire system wouldn't feel as engaging to interact with as it should be, rather feeling like a chore players do to get benefits.

A FIRE-BACKED ECONOMY

With the fire drain ability allowing the player to regain mana from fires, a new concept was introduced to the game's balance, that is the idea of a "Fire-Backed Mana Economy". Fires would have a mana cost, and the player would be able to "invest" their mana into fires, which would pay their "dividends" in providing direct damage and player buffs that are tied to how much fire is around them. This "investment" can even grow thanks to the fire spread mechanic, and it can be "cashed out" thanks to the fire drain ability, potentially recouping some or all of the investment put in and even turning out a net profit.

That was an Eureka moment for the project's balancing. The player's mana pool, special abilities, the properties of every entity and NPC, all of that suddenly could serve a common design philosophy rather than just existing as separate systems that had to somehow play nice with each other. And the best part is that most of the work required to adhere to this new philosophy has already been laid out - the variables have been there for a while, it's just a question of tuning them correctly.

THE MANA TO FIRE EXCHANGE RATE

The first big change this philosophy brings is actually something that has already been sort of a "soft concept" in the game's balance: the idea that the player trades mana for fire. Each special ability has a "fire damage" component which is what ignites flammable objects - deal enough fire damage to an entity, and it will start burning. This damage can coexist with other damage types such as physical or explosive, but fire damage is the only one that can ignite flammable objects. The simplest fire attack the player has at their disposal is the Firebolt, a simple ranged attack that can hit only one entity per projectile and deals a small amount of pure fire damage. It is the perfect baseline for our new balance strategy, having a 1:1 exchange rate between mana cost and fire damage. 20 mana for 20 fire damage at the time of writing.

Other special abilities are a bit more difficult to balance, since they may be used to strike at multiple objects per use, or have other utilities that warrant a higher mana cost. For example, the Fire Spray can be used to strike multiple targets for 50 fire damage each - so putting its cost at 50 feels like too much of a bargain. Currently I have it at 100, which would make it "break even" if at least 2 targets are struck. The next special is the Fire Slam, which only deals 15 fire damage, however it comes with a special knockback effect that can be used to create space and even deal further physical damage by knocking entities into the environment or each other. So let's experiment with its cost being 50 - with 30 covering the cost of two targets, and the extra 20 accounting for the added utility.

Gosh, this is like setting prices for products, isn't it? Currently, the philosophy is that no player ability should be consistently dealing more fire damage to a single entity than its mana cost. More fire damage spread between several targets or dealt inconsistently is fine, but should be accounted in the "pricing" of each ability.

THE CAMPFIRE HIERARCHY

One inspiration behind KatFS's fire mechanics harkens back to my days in the boy scouts, where we would learn how to start campfires. If you aren't familiar with the process - there's a hierarchy to the fuel in a campfire: kindling such as dry leaves or tiny twigs will catch on fire very easily, but also burn out just as fast. Medium wood such as branches require more heat to catch on fire than what a match will provide, but will last for longer, and larger logs are tough to burn but once they do they'll last for hours.

This "hierarchy" has always been on my mind as I designed the basics of the fire system, with each entity having configurable parameters for how much heat it needs to burn, how long it will burn for and how much heat it produces. However, these variables have been treated mostly as a cosmetic aspect without many gameplay implications for the most part. With the "Fire-Backed Mana Economy" philosophy in place, there's now an incentive to implement the "campfire hierarchy" into the game's balance. Entities can now be designed to function as the kindling, the intermediate fuel and the long-burning stuff; and I could even throw some fun oddballs around such as volatiles, live wood, or perpetual burners. When the player "invests" their mana into creating a fire, there's now a strategy behind it.

• "Do I have enough mana to set this large object on fire, or should I go for the smaller ones instead?"
• "How long will this object burn for if I ignite it, and how can I make the most out of it?"
•  "I finally got this big object on fire through strategic fire magic use, should I drain it for a big mana profit or keep it going for longer for the buffs?"

This also means that the gains from draining fires should take the properties of the objects being targeted. By default, objects need to accumulate 100 heat points to catch on fire, making the baseline "investment" for a fire be 100 mana points. However, entities can have their heat intake modified so that it effectively needs less or more heat, changing the needed investment. When a fire is drained, this modified value needs to be taken into account - a fire that took 5 times as much heat as another should give 5 times more mana back when drained.

WHAT'S IN IT FOR THE PLAYER?

So, that's cool and all, but ultimately there has to be a motivation for the player to invest in making fires, otherwise this whole economy falls apart. KatFS has several rewards for engaging with the fire system built into its design, most of which have already existed to some capacity since the earliest concepts of the game.

The first and primary reward for creating fires is the Fire Energy System, which provides buffs for the player based on how many fires they're surrounded by. Think of it as the heat of the fire super-charging Kalia's magic. Having Fire Energy buffs the player's fire damage output and makes the heat spread from existing fires stronger, tipping the scales of the "Fire-Mana Economy" into the player's favor and potentially causing a snowball (fireball?) effect. However, this is offset by different fires providing different amounts of energy, and with fuel for the fires being a finite resource. The campfire hierarchy is also into play here, with kindling providing small amounts of energy for brief periods of time while long burners will keep the bar filled up for a while.

The aforementioned Fire Drain system offers an incentive for the player to not only get their fires to multiply, but also to clean up after themselves, restoring some or all of their mana in the process and leaving them ready for combat without having to rely on the slow mana regeneration or potions.

Fires also obviously have plenty of direct use in the game's combat encounters. Setting an enemy on fire will have them take damage over time and eventually have them defeated or at least left in a weakened state. NPCs, just like other entities, can also spread fires and have fires spread onto them, with their erratic movements potentially taking your flames further, for better or worse... And finally, let's be frank: it's just plain fun to spray a horde of spiders with flames and watch them panic!

HOW IT ALL COMES TOGETHER

This philosophy is in place, but now it's my responsibility as the game's designer and developer to adhere to it, through clever ability, encounter and level design. Just like elements such as explosive barrels should be placed with some thought behind how the player will interact with them, so should the elements that make up the game's fire system. 

Objects need to be placed close together so that fire is allowed to spread between them, with the paths it may take in mind. There also needs to be consideration on how the player may create or stop the spread of fires beyond what's placed in the level, by moving things around, destroying objects or pumping more fire damage into the system to accelerate the fire spread. The campfire hierarchy needs to be considered, with kindling placed cleverly around big burners so that the player can take advantage of them to create bigger fires with less of a mana cost. And obviously, just as you would place cover objects, health pickups and explosive barrels in a combat area of the level; flammable objects should also be placed with their combat use in mind. That huge dead tree in the middle of the zombie horde arena? Light it up, and you'll be treated to a massive damage boost and enough heat to burn all the zombies for the whole encounter!

This has been a more elaborate devlog on the new balance philosophy behind Kalia and the Fire Staff! Thanks for reading, and if you're interested in the project, check it out here or over on Twitter (still not calling it X). The game has a pre-alpha demo featuring 3 chapters which you can download and play right now!