Natural Mechanics

Every game has some kind of rules and mechanics that say how it works. One quality criteria of these mechanics is something that I call their naturalness. Some mechanics feel more natural than others. If a mechanic feels natural to the user it is more likely that he will accept and learn it faster than a mechanic that feels constructed and artificial. This way it is easier for him to get immersed in your game and have a more satisfying experience. The following article tries to explain the concept of natural rules, its values,risks and chances.

What is a natural mechanics?

Humans develop mental models that tell them how different things work. Take gravity as an example. When you drop an apple you’re going to expect that it is going to fall down to the ground because of your mental model that tells you how gravity works. In the same way players develop a mental model of your game. But their mental model of your game is affected by other already formed mental models that are somehow related to your game. The more your game matches their already established mental models the easier it is for them to learn and accept it. Of course not every game wants to be a simulation of the real world so you have to make decisions what things you’re going to simulate and how completely you’re going to simulate them. Therefore finding a good representation in the real world to communicate a mechanic in your game has a very high value. So you can think of a natural mechanic as a mechanic that its representation in the game matches the users already formed mental models and expectations to such a degree that it is easily learned, understood and remembered.

Sources of mental models

There can be different sources where humans develop their mental models from. One big source of mental models are physical or natural laws. Gravity pulls us down, force leads to movement, etc. Video games make a lot of use of these models. Physic based games like Cut the Rope for example rely almost completely on these kinds of mental models. This is probably a reason why Cut the Rope had such a wide user base as almost everybody could pick up the game and understood its mechanics in such a short time. The players could make use of their already developed mental models of physical laws and Zepto Lab (the developers) made great use of this advantage.

Another big source is society. Killing the king in chess leads to a win as a rule is easy to accept because based on our knowledge about how society works killing the leader of a group has such a huge impact on the group that it may lead to the decay of it. There is no real reason why all the other pieces on the board shouldn’t be able to keep fighting as soon as the king is dead. Our mental model that describes how important a king/leader in a war is lets us accept it and makes it easy to remember.

The last big source of mental models are conventions. Conventions tell us that a cross at the top right of an interface closes it and that we can manipulate the view in a first person shooter with our mouse. You can see these kinds of conventions more often at more artificial mechanics. Take the level up mechanic that a lot games have today. A lot of games teach players that having a level up means to progress in the game. This became a convention that video games formed over time. Having a level up mechanic is something that most players understand as soon as they see it because they played so many games that featured and taught them the level up mechanic.

Natural Mechanics Done Well

I love Dark Souls. It has such a deep melee combat on the one hand on the other hand its combat feels very natural. From Software did a great job in adding mechanics that make the combat deep without making it somehow artificial. Let’s take a look at the rules of the melee hit mechanic.

• Hitting an enemy deals damage
• Hitting early in the enemies hit-animation can interrupt him
• Hitting costs stamina
• Hitting costs time
• Hitting costs weapon durability
• Hitting a wall cancels the hit
• You can’t turn while hitting
• You can’t walk while hitting
• Hitting all the time keeps the player's stamina from regenerating
• Weapons that are too heavy for you are harder to handle
• Hitting with both hands costs more stamina and deals more damage
• It matters where you hit your enemy
• Different weapons have different hit animations
• Different weapons have different range

As you can see just hitting has at least 11 mechanics. Hitting enemies is an action that the player will perform a lot so having a lot of depth in it is something important and healthy when you have such a core audience like the Souls games do. But none of these rules is too artificial. It is easy to accept these rules because they are very close to the real world. The only rule that feels a little artificial in my opinion is the one that says that animations are only canceled when the enemy is hit in a specific time frame. I may be wrong but I think that it doesn't matter too much when you hit someone with a sword to keep interrupt his movement. But it adds a lot of depth by providing a risk and reward mechanic, as players can try to hit the enemy and interrupt him before his hit animation is too far to be interrupted. But when you want a mechanic like this you have to consider if it is worth it. From Software strives for depth and has a lot mechanics that are explained inside the fiction of the game in a very natural way. Holding your shield up slows down your character's stamina regeneration (risk and reward), losing all your stamina leads to an exhaustion state (resource management) etc. All these mechanics are almost self-explanatory. From time to time they make use of dialogues to explain mechanics that are more abstract or artificial but as their user group are mostly core gamers that are willing to learn and remember new stuff it isn’t a game breaker at all.

Natural Mechanics Done Poorly

One of the most present examples is the energy mechanic in free to play games. The usage of this mechanic is clearly obvious: pacing the content and monetising the player. But to be honest, in a lot of games, related to their theme this mechanic doesn’t even make sense. A lot of games do not even try to disguise it inside of their fiction. They just call it energy and that’s it. As energy is a pretty easy mechanic most players get it. Even more because of the time it became some kind of convention so players nowadays are not even confused when they meet an energy mechanic.

Another example is the fusing of monsters like Puzzle and Dragons did. In Puzzle and Dragons players can fuse monsters with other mothers so the first monster becomes stronger while the other monsters are lost. The mechanical benefit is clear (everything that the player get’s should have some kind of value, so even “bad” monsters that the player didn't want can be used to progress monsters the player wants to level up) but to fuse random monsters so they become stronger is very artificial and hard to understand. Especially for players that are not used to this kind of games. There is just no real world example that works this way.

The Game Setting

The setting of your game can make it harder and easier to find representations of your mechanics that make them feel natural. Blizzard always chooses settings that give them a lot of freedom when creating mechanics. This mechanical freedom comes with a cost. They have to work on their visuals so players can learn and understand what is going on. They still manage to have some kind of natural representation quite often but sometimes even Blizzard struggles with this and players just have to learn the mechanics that determine how their games work. For example the human race in World of Warcraft had a skill that gave them the possibility to see stealthed enemies even from a very far distance. This is hard to explain because it is not the first thing that comes into someone's mind when you think about race specific skills that fit to a human race.

But more casual game companies like Zynga take huge advantage of already formed mental models with their choice of setting. The very well known farm setting that was featured in Farm Ville was so intuitive that their players could learn the game very quickly as almost everybody already had some kind of idea how things work at a farm.

Graphics And Expectations

The more realistic your game looks the more simulation players expect from it. So if you have a very toony style players are more likely to accept it if things do not work in the same way as their already formed mental models of the real world. The more your game looks like the real world the more they expect that your game will work that way. Take a look at Mario Kart and the Grand Turismo games. Both games are about racing but Mario Kart looks way more abstract and cartoonish, as a result it has much more freedom for artificial mechanics like Power Ups, crazy short cuts and coins that are on the street and grant speed by collecting them. Grand Turismo on the other side looks way more realistic, so players expect that their cars and the mechanics behave in a realistic way and that’s exactly what this game is trying to accomplish.

With good intentions comes acceptance

Sometimes it is just a matter of communication. Even an unnatural representation of your mechanic can be accepted when it is a rewarding mechanic. This doesn’t make the game easier to learn but at least players won’t be mad about it. A mechanic that looks artificial but gives the players some kind of benefit or reward is something they can accept. But the opposite is harder to accept. That means that when you have mechanics that are more a restriction or some kind of punishment to your players you even have to try harder to find a good representation that makes your mechanic more authentic. A good representation can even make a mechanic feel good even if it is a restriction. In World of Warcraft Blizzard had the mechanic that let players gain less experience after playing for too long. They communicated this mechanic by saying that the avatar was exhausted and now earns only 50 percent of the rewarded experience. Players hated it and Blizzard had a hard time to justify this mechanic. So they took another approach and communicated it the other way. Now the avatar was rested when players didn’t play for some time and got bonus experience. Only after playing for too long the character state fall back to the normal amount of experience that he gained from defeating monsters and finishing quests. It was the same mechanic and even the representation was as artificial as before but now it was communicated as some kind of bonus. The feedback was much more positive and players loved it.

How to apply

Try to make use of already formed models of your players as much as you can but first you should design your mechanics. The already formed models of your target group can even work as an inspiration for these mechanics but they shouldn’t be the only source for your ideas. As long as you are able to explain your game to your target group in an enjoyable way everything is fine. Maybe the first representation of your mechanics isn’t the best, go and try to find a representation that is closer to another established mental model that explains your mechanic in a better way. If you’re not able to deliver a great representation make use of something that is as good as possible and see how if and how it works out. Sometimes chances are good that co-workers are able to come up with ideas for representations that fit your mechanics much better. At the end you have to ponder if certain mechanics feel to arbitrary and artificial to your players or if you can make use of them. Iterate and try to come closer to the best representation of your mechanics but always keep the initial desired experience and your target group in your mind. Never forget your desired experience, if you can deliver a mechanic and a representation of this mechanic that fits your desired experience you did a great job. Good luck with that!

Mechanical Value and Variation

A guide for gameplay variation

Gameplay variation is an important aspect to keep the game experience fresh. There are two different kinds of gameplay variation in video games.

• Mechanical Variation
• Numeric Variation

The following article will explain the differences between the two and hopefully provides helpful tips on how to develop gameplay variation for your game design in a structured way.

Gameplay Variation

Gameplay variation is the kind of variation that provides a number of different experiences when it comes to the gameplay of your game. Gameplay variation helps to give players different kinds of experiences when facing the challenges in your game. Every gameplay variation you add to your game should add some kind of value to the possibility space that your players can experience in your game. As long as the player is able to learn, explore and practice new things about your gameplay chances are good that he doesn’t get bored.

Mechanical Value and Variation

Your game will have a gamestate. Players will have a mental model of your game and the current gamestate that tells them how they think your game works and (in the best case) a goal they want to achieve. Usually they try to manipulate the gamestate to their favor until the gamestate says that they have achieved their goal, the game is over or they quit the game before. Players manipulate the gamestate with the their input device to interact or make use of the accessible gameplay mechanics in your game. For example: Lets take a look at a very simple imaginary game, a FPS with conventional controls where players are on a blank field and are able to move, aim and shoot with a single weapon. The goal of the game is to set the hit points of every enemy player to zero by shooting at them. Players will try to use moving, aiming and shooting to manipulate the hit points of their enemies.

Every gameplay mechanic you add to your game should give your players things to consider when it comes to manipulating the gamestate to their favor in achieving their goal. A gameplay mechanic that isn’t relevant in a meaningful way for any of your players through the entire game is a useless mechanic. The more a player has to consider how to make use of specific mechanic the more value it has. Moving, aiming and shooting are very closely related to each other in a FPS. By moving around you can also change your view and make it harder for other players to hit you. With aiming you can control if you will miss or hit your players when you shoot. Every mechanic in those features has to be considered and used almost all the time in relation to each other when players try to manipulate the game state to their favour as they try to win the game.

A lot of FPSs do not have only one level that is a blank field. Usually they have some kind of environment. As you can already imagine, this mechanic also has a very strong relation to every other mechanic. Now players have to consider their surrounding environment all the time. Moving, aiming and shooting can have huge dependencies to the environment so you can say that adding environment may be a mechanic with a lot of potential.

If we want to make the most use of our different mechanics, we have to take a closer look. I guess you already thought that adding environment is in fact not just one mechanic, and you’re right. There are at least 3 mechanics. Let’s take a look on how the environment mechanics affects our player when it comes to the gameplay:

• He may not be able to walk through
• He may not be able to look through
• He may not be able to shoot through

There is a method that I really like when I want to squeeze the most variation out of a single feature like “environment”. I take a look at the dependencies of the different mechanics and think about them as bool variables and combine them in different ways. A bool variable is a variable that has a true/false state. Let’s take a look at the table:

	Metal Wall	Wood Wall	Glass	Bulletproof Glass	Fog	??	??
Can shoot through?	No	Yes	Yes	No	Yes	No	No
Can look through?	No	No	Yes	Yes	No	Yes	No
Can walk through?	No	No	No	No	Yes	Yes	Yes

As you can see, here we can come up with ideas that we can definitely prototype and see how they feel and how much value they add to the gameplay experience. Take the most promising combinations first and see how much value they will add to your game. As you can see I left the last two examples blank, maybe you can come up with ideas by yourself? :-)

Bool variables describe mechanical variation and give you a good sense where you can look for promising gameplay elements for your game. It won’t save you from prototyping and iterating but it gives you a methodical approach on how to proceed when looking for variation.

Strong dependencies between different mechanics can lead to a lot more different game states than single mechanic could do on their own, as a well known quote says: “The sum of the parts is greater than the whole”. If the player is able to manipulate the game state he should be able to make a decision based on the currently provided information on how to manipulate the game state to his favour in the most promising way. As soon as the game and the player arrives at the new game state he should get some kind of feedback that provides new information and the cycle repeats itself. The more game states your game can have, based on the mechanics you provide, the more your player is able to explore the different possible outcomes and is confronted with situations with uncertainty where he has to make decisions on how to achieve his desired game state. This is something good, as your game keeps providing something to learn for a long time.

Adding new mechanics is easy, adding new mechanics that have a lot value and can lead to a lot of variation in the different game states is hard.

As every new mechanic is something your player has to learn until his mental model is complete enough to make educated decisions in the different game states, it is even more useful to have lesser but stronger mechanics.

Different weapons in FPSs are a common way to add variation. To have a mechanical variation between your weapons you have to take a look at the fundamental mechanics that describe them. There is no mechanical variation between a machine gun and a pistol. But there is a  mechanical difference between pistol and shotgun that fires several projectiles that spread in different directions. Of course you can go always further with mechanical variation like adding mines or other things that work fundamental different than other weapons in your game. But as soon as you add a new feature, think about the fundamental mechanics that describe this feature and think about possible mechanical variations. This is mechanical variation in gameplay. Now let’s take a look at numeric variation in gameplay.

Numeric Variation

As I already said the variation between a pistol and a machine gun doesn't lay in their mechanic it lays in their numbers. The variable numbers that are placed inside the functions of the code make the difference between a pistol and a machine gun and give them their different flavour not their mechanics. Let’s make a list of all the numbers that could be important to describe a possible gun mechanic.

• Damage
• Range
• Projectile size
• Projectile speed
• Projectile Weight
• Shooting frequency
• Weapon Weight (Slows movement)

As you can see these are at least 5 mechanics in a simple gun that need numeric values and there are a lot of FPS out there that have a lot more mechanics in their guns. These numeric variables are very mighty and can provide variation that is valuable and not as expensive in terms of effort as adding completely new mechanics. This means that as soon as you have enough mechanics that need numeric variables, this could be a good place to take a look when you want to add variation to your game. It is also valuable because players do not have to learn something new. It is just different, but not new: The rules are the same just the numeric values differ from each other.

There is a efficient way to look for possible numeric variation in your variables and it is very similar to the method that I already showed you above. You make a table with all the different numeric variables and add different values.

	Weapon 1	Weapon 2	Weapon 3	Weapon 4
Damage	Low	High	High	Very Low
Range	Medium	Low	Very High	Medium
Projectile Size	Small	Very Big	Medium	Normal
Projectile Speed	Fast	Slow	Very Fast	Medium
Projectile Weight	Light	Heavy	Light	Light
Shooting Frequency	Slow	Very Slow	Slow	Very Fast
Weapon Weight	Light	Very Heavy	Heavy	Medium

With this kind of technique you can explore the possibilities of your already implemented mechanics even further in a structured way. This won’t save you from iterating but it helps you to get an overview about the possibilities. The stronger the numbers differ from each other the better are your chances that your guns / units / skills / etc. will feel different in a meaningful way so they will add variation and work as a true alternative to consider for your players when they want to manipulate the game state to their favour. This will make your game experience richer as different players are biased to different types of gameplay.

If you are not able to create meaningful variation within your available mechanics and variables you may consider adding new mechanics. Maybe we have the feeling that our guns are not able to provide gameplay that creates enough value for the gameplay experience. So let’s add ammo and reload mechanics that will add more variables, this time we will see a mix from the bool and numeric variables.

Here are your variables and a few examples:

	Weapon 1	Weapon 2	Weapon 3	Weapon 4
Needs ammo?	Yes	Yes	Yes	No
Needs to reload?	No	Yes	Yes	-
Magazine Size	-	High	Low	-
Max Ammo	Low	Medium	High	-
Reload Time	-	Slow	Very High	-

After you have added this mechanic you can look for different combinations and try promising outcomes. If you want to go further you can think about adding a new mechanic to acquire ammo.

This may look like the following:

How to acquire ammo	Weapon 1	Weapon 2	Weapon 3	Weapon 4
Walk over ammo	Yes	No	Yes	No
Regenerate over time	No	Yes	Yes	No
Ammo Regeneration / sec.	-	1 / sec.	0,2 / sec.	-

The number of different combinations grows exponentially. You will develop a feeling on when to add new mechanics and how to play with the different variables that you already have. This tool helps you to stay on track and may discover potential.

Last Words

You may have a game where you have a lot of trigger mechanics, effects, conditions and targets that describe how specific things work in your game (Hello Hearthstone). So you may have more dimensions. In this situation you may have to invent your own approach on how to look for variation in your mechanics. The most important thing is that you get a feeling for possible combinations from the mechanics that you already have. List everything that you have and check all the possible combinations with an systematic approach. How can you recognise the different combinations of your mechanics and how can you add even more variation with their numeric variables? The best thing you can do is to create some kind of tool with your programmers that gives you the possibility to make use of the different mechanics and combine them in an effective way. Just keep in mind to have a systematic approach. It’s cool and fun to just add random effects and triggers and combine them as you like but you run in danger of missing potential and lose a lot of time. You all worked hard on the different mechanics in the game, so why shouldn't you make the most use of them. :-)

After all you still have to know what kind of experience you want to create with your gameplay mechanics. This methodology can help you to take a closer look on how to achieve it with your already implemented mechanics and when you may have to add something new to achieve your desired experience.