Just adding a second player to a game does not make for a good co-op game. The developers of Shadow Puppeteer explain how they approached co-op based game design.

Cooperative games challenge players to work together (i.e., to succeed or fail as a team as they strive to reach a common goal). In these games, players can have identical or differing abilities.

But not all co-op games are created equal. Some co-ops are engaging, giving both players a sense of purpose, while others cause frustration or apathy due to an imbalance in the distribution of player skills. So, what makes a good co-op experience?

This was the central question we at Sarepta studio asked ourselves as we began development on »Shadow Puppeteer«, our award-winning, local co-op adventure. To properly answer it, we turned to other co-op games published throughout time to pinpoint what exactly it is about these games that makes them deliver an unforgettable and unique experience.

Our analysis and internal discussions resulted in the identification of three components that we believe define what we call »true co-op games«.

1. Relies on Two or More Players

Good co-op games usually offer players two ways to play the same version of the game: The first is playing by yourself, and the second is playing with another person. But, unless all players are integral to the completion of the game, there is limited incentive to cooperate.

For example, »Little Big Planet« has sections that players can only access and complete if they have the minimum required number of players. By comparison, the NES title »Chip ‘n’ Dale Rescue Rangers« can be played in both singleplayer and co-op. In this example, the addition of another player makes the game easier because it’s more accessible to less skilled players.

2. Gives Each Player Different Roles/Skills

Very often in co-op games, characters have identical roles or skills and adhere to the same rules. This is what we call »symmetrical co-op«. This can result in players dividing tasks throughout the game between them to increase efficiency. This can also, and most often does, result in one character performing all major actions, while the second simply »tags along«.

In contrast, some games are completely asymmetric, having no overlap in gameplay between players. This lack of overlap creates a dependency between players, but can sometimes create too much of a divide. In Shadow Puppeteer, players exist in different worlds. If they had absolutely nothing in common, it might sever the sense of a »shared experience«.

We found that by giving players at least some unique mechanics, and demanding these to be combined in order for them to progress, ensures that both players are integral and become active participants in the experience.

A good example, of how different player skills can create an engaging co-op experience is »Trine 2«. In Trine 2, players control three characters with different abilities: The wizard can cast spells that move or create objects, the thief can use a grapple or a bow and arrows, while the knight has superior fighting abilities and strength. Conversely, in »Halo 3: ODST«, both players play an Orbital Drop Shock Trooper, and although they can choose to equip different weapons, each player’s skills and abilities are identical.

3. Gives Each Player Equal Importance/Number of Tasks to Perform

True co-op games engage all players equally. Whether players have different or similar skills and abilities, it’s important that they both feel like they have enough to do and are actively contributing to the progress of the team. Players may not be entirely objective here, so it will not be enough to merely listen to their thoughts. Close observation may also be needed.

In »Ibb & Obb« both characters are presented as equals. The two can either move in the world above the ground with regular gravity, or use portals to walk upside down in the world below. However, some portals can only be used by specific characters. This ensures that both players take an active role and contribute to the team’s progression. I.e., both the path above and below offer challenges, and players must take turns performing tasks in order to advance as a whole.

Another example of this is »Paul & Percy«. Unlike Ibb & Obb, Paul & Percy utilizes a switch mechanic between the two characters, enabling single player. The characters Paul and Percy have the same abilities, but are separated on either side of screen. This means the characters take turns moving objects on their side to enable both to progress, creating a natural flow of »back and forth« gameplay.

Making Shadow Puppeteer a »True Co-Op« Game

At Shadow Puppeteer’s core lay the premise of a boy and his shadow, and the idea of »what would happen if the Boy’s shadow came alive?«. I.e., how would gameplay differ for each of these characters, or what similarities would they share?

The premise created a natural divide between the players. Separating them into different »dimensions«. The Boy could operate in 3D space, while the Shadow only existed in the 2D world. With this, we created an internal logic that communicated each character’s unique value to players well, making it easy to understand why certain actions and places were accessible to one character and not the other.

Originally, we tried to give our characters different core mechanics, but due to the fact they existed in different dimensions, already set them apart. This created too much of a divide and made it difficult for them to relate to one another. Therefore, we gave them similar core mechanics, but unique complimentary mechanics. These shared actions also fit the narrative well, as both characters are connected (i.e., one is the other’s shadow).

In addition, we gave each character the same basic interaction skills, such as moving crates, pulling levers and carrying lids. The difference was that only the Boy could interact with objects in the »real« world, while the Shadow could only interact with the shadows of those objects. Doing this gave us the opportunity to create puzzles where part of the solution involved figuring out which character needed to interact with what. For example, having one object’s shadow cast within another shadow, made it inaccessible to the Shadow character. Similarly, placing objects in the background or foreground could bring them in or out of the Boy’s reach. Via the individual skills in the complimentary mechanics, we made both players necessary to the progression of the team, while still making them feeling connected.

Each character also has unique skills. For example, we altered the Shadow’s gravitational pull to make him drawn to the closest, strongest light source. This enabled the Shadow to reach new and interesting locations within levels. In addition, both characters have skills that are dependent on actions being performed by the other. A good example of this is when the Boy uses a lantern to cast shadows against the wall that the Shadow can pick up and use. These types of abilities force players to communicate and work closer together.

Balancing Action and Importance

To give each player an equal sense of purpose, the number and importance of tasks each character performed had to be balanced. To illustrate an example of how we did this, let’s look at an early level called »Home«.

In Home, the Boy can progress through the first section of the level by climbing a ladder. However, the ladder only exists in the 3D world, which is inaccessible to the Shadow. To help the Shadow progress, the Boy must pull a crate from the shadows into the light to create a platform for the Shadow to jump to.

At the next stage of the level the shoe is on the other foot. A tree branch in the foreground is casting a shadow, creating a platform for the Shadow to use to advance. But, the branch is too thin for the Boy to use as a platform. The Shadow must now create a suitable platform for the Boy by pushing a crate’s shadow, which in turn moves the physical crate into the Boy’s reach. The »first one, then the other« nature of play creates a dynamic that emphasizes the importance and dependency of both players and balances the amount they have to do so their involvement feels equal. We found there was great effect and enjoyment in switching the power dynamic between the players, alternating who was helpful and helpless in this manner.

Creating Co-op Narratives

If your game has any kind of narrative, you need to think about the story’s progression. I.e., what is happening in the story and how does that affect your character(s) physically and emotionally. Or, are there changes happening to the character that should be reflected in the gameplay?

With a co-op title, your characters should have equal story progression. But the question is, how can you achieve this? Most classic stories have one protagonist, reducing other characters to helpers, givers, or villains. If you cast one of the players in the traditional hero role, the others will automatically be less important, as their role is defined by their relationship to the protagonist. We found it is important to give each character story development, making it impossible to have a traditional protagonist. But then other questions must be considered: Should the characters develop in tandem or asynchronously? How do their experiences coincide? How do they differ? Try to divide the story into two and consider it from each character’s perspective, as each character may be affected by the same event in different ways.

We wanted both characters to have their own distinct purpose – mechanically and emotionally – so we decided to create a rich backstory. Even though our players would only be told a fraction of this backstory, even the simple facts about our characters that we told enriched our gameplay. This kind of exercise also helps create consistency in the development of characters, style and gameplay.

In Shadow Puppeteer, we realized our story was centering around the villain. He is the one who incites and creates conflict. He is the focal point and catalyst for the development of the story, and is responsible for bringing the players’ characters together. And, even though his story is only hinted at through the game, he actually has the most character development.

One helpful tool we used to ensure that the introduction and frequency of gameplay elements was well portioned, is something we call »skill charts«. In our skill chart for Shadow Puppeteer, we noted when gameplay elements were introduced and in what levels they were used. By getting an overview like this, a skill chart helps balance progression by revealing if certain gameplay elements are far more frequent than others. Skill charts can be a useful tool to balance progression, whether it is a singleplayer or co-op game. For our Shadow Puppeteer skill chart, we made notes of when the individual players performed each action. This enabled us to understand the level of importance and participation each character had throughout the game.

Conclusion

Most game development projects have different starting points. Depending on a developer’s vision, his/her game might be inspired mostly by mechanics or by narrative. Either way, we found that it’s crucial to let the co-op nature of the game guide every part of the design. Co-op is not something you can add toward the end of development and expect to deliver a satisfying and balanced experience to players. You must commit to co-op and make your characters equally important throughout the gameplay experience. This is the best way ensure you provide joy and engagement, and avoid the tagalong trap.

Catharina Bøhler, Marianne Lerdahl

This feature was originally posted on the development blog of Sarepta Studio: http://shadowpuppeteer.com/blog/

About the authors

Catharina Bøhler (left)

is Co-Founder and CEO of Sarepta Studio.

Catharina Bøhler is one of the co-founders of Sarepta studio, a Norwegian 3D visualization firm, independent video game developer and creator of »Shadow Puppeteer« – an award-winning, asymmetric PC and console game. Catharina holds the position of CEO.

Marianne Lerdahl (right)

is Co-Founder and Project Manager/Producer of Sarepta Studio.

Marianne co-founded Sarepta Studio in 2010 and first worked as Web Designer and Illustrator, switching later to Project Management. Today she works as Project Manager/Producer for Sarepta Studio.