How Stray Was Made and Inspired by an Overpopulated City

Stray’s development story started with two artists and the dream of making their very first indie game together. Viv and Koola, who have indicated in multiple interviews they prefer to go by their nicknames, left Ubisoft Montpellier to create their own indie studio. While coming up with an idea for their first game, they couldn’t help but be inspired by a now demolished city called Kowloon Walled City. For about a hundred years, it was located on the outskirts of Hong Kong and also went by the name the City of Darkness. During its prime, the city was a very tightly packed urban living district with an immense population density of more than 110.000 people per square mile. Its extremely compact environments made for unique city landscapes that felt both organic and dark. Kowloon City inspired many media franchises like the Ghost in the Shell anime, the Bourne series, Christopher Nolan’s Batman and Call of Duty: Black Ops.

Though the lawless city was demolished and replaced by a park in 1994, Viv and Koola grew fascinated by its detailed architecture. In 2015, they started working on a project they then called ‘HK Project’, supposedly short for ‘Hong Kong Project’. After creating an initial prototype they noticed how a city like Kowloon, with all its passageways, tiny windows and high rooftops, would be the perfect playground for a cat. Only a cat would be able to move through such a city freely, and discover all the stunning multi-level points of view.

According to Stray’s producer, Swann Martin-Raget, the ball started rolling from there. “That’s really the moment where the project started to take precise shape in their head. They’ve been working on this with a lot of gameplay intention. It was clear very early on that they wanted to do an adventure game; that the story of the place was very important, and the pacing of the game, the action sequences and everything. They really had a lot of ideas, and they were really inspired by the concept.”

Starting in October 2015, Viv and Koola shared concepts of visual gameplay scenes, captured in Unreal Engine 4, revealing they were working on a cat adventure video game. From the comfort of their apartment, the two developers started working on a first gameplay demo. In January 2016 they shared more concepts of a playable cat walking and jumping from block to block. Viv and Koola were studying animation and at the time were struggling with the correct collision mechanic for the cat character. Character control in Unreal Engine 4 mainly focuses on animations for characters with two legs, not four legs, and so the cat’s head kept colliding with and passing through walls while moving it on and over obstacles. Jumping and fall detection also proved tricky for the duo.

In April 2016 Viv and Koola hinted at the presence of robots in the game, sharing more graphic tests later in May and June that showed robots in the background of certain scenes. That their vision was strong and had potential, was confirmed that same year when Viv and Koola were contacted by Annapurna Interactive, the video game publisher now known for games like What Remains of Edith Finch, Outer Wilds, The Pathless, and many more. However, in 2016, Annapurna had yet to publish its first game. Even so, Viv and Koola accepted the opportunity and signed a funding deal with Annapurna Interactive to develop and publish ‘HK Project’.

Now that the two developers had access to more money, they started expanding their team to a total of five people. From the very beginning, they preferred a small development team over a large one, since this would ensure direct communication amongst the team, and ensure that their vision would stay the same throughout development. This also meant the game’s scope would have to remain small, as Viv and Koola had intended. With a smaller team came production constraints, which influenced narrative decisions early on. For example: at the start of development, the team also did tests with human npc’s. According to Swann, the team then realized animating human characters would be a very time-consuming process.

“We did tests with humans at the beginning, and it’s true that to have a visual rendering that satisfied us, it was quite complicated, it’s really difficult to transcribe humans correctly. So we did some tests with things that were easier to do, i.e. machines, because it’s easier to model and sometimes to animate. And when we started these tests, we found ourselves really super inspired by everything that brought, first as visual contrasts between the cat who is small, who is cute, who is very organic and the robots which are colder and more angular.” This ended up resulting in a robot-filled world and steered the story in a new direction. The team had to answer a whole set of new questions, most importantly: where are the humans? What had happened to the city? How did the cats and robots survive it?

The player can answer these questions by solving cat-tailored puzzles to progress the storyline. The fact that the player controls a cat instead of a human, poses an interesting set of unique level design challenges and opportunities. Only a cat could jump up high or crawl through vents, making it more than your average 3D platformer because of the verticality. Every pipe that wraps around a building, every aircon unit that hangs outside of a window, a cast-iron grate or even a small bucket hanging on a rope offers a new route, making great use of environmental storytelling to expand the narrative. As a result, Stray’s sandbox areas are very compact and filled with content, requiring meticulous design and a huge amount of testing. The developers spent hours with new players who would tell them where they wanted to be able to go in the game, and it was a very specific process that had to fit Stray’s unique approach to level design. The camera angles also proved challenging, since a cat can move through any small space.

The devs really wanted to reward players who explored, since they included so many small details that add to the overarching story of the city and its inhabitants. Every new gameplay element had to add to the backstory and the world the team was building. Another important element of the level design was the sense of alienation the developers wanted to instill. As a cat in a big cyberpunk city filled with robots, the city is supposed to feel unwelcoming. One of the ways the team achieved this is by developing a new alphabet for the game, so that players don’t understand every element of the city. That’s where the robot B12 comes in, its skills being complementary to those of the main character. B12 helps the feline protagonist to translate the language of the city’s robots and to solve some more complicated puzzles a cat wouldn’t be able to solve by itself.

While the puzzles really help to set the scene and tell stories through the environment, the game alternates with intense chase scenes. The swarms of Zurks were inspired by bedbugs that once bothered Viv and Koola. These intense gameplay sections are meant to add more variety and to ensure progress is always surprising and interesting, essentially keeping the players on their toes. In the early stages of development, the player was able to manually jump to ledges and onto surfaces. However, players kept missing the jumps. The team decided to instead give the player prompts to auto-jump, to remove the possibility of failure and avoid frustration. Always successfully making a jump also lined up with the expectations of playing as a cat. It allows players to focus more on the experience, environment and story, rather than on the difficulty of making the jumps.

In order to make the game as immersive as possible, the devs opted for a third-person perspective, low camera angle and a very minimal user interface for deeper observation of the environment. But the team went a lot further to make sure the experience felt cat-like, paying immaculate attention to playful and lively cat-like behavior in order to come up with ways to translate that behavior into the game. Therefore, things like the dedicated meow button seemed like a no-brainer to include. But just getting the basic movements of the cat right, proved challenging for Miko and Rémi, BlueTwelve’s cat programmers. They worked many hours to find the ideal balance between good animations and responsive gameplay.

“The majority of the animations were made by one person, Miko, our cat’s animator, who is really talented with key frame animations like more traditional animation. So we naturally started the project this way, and as we moved further we heard about studios that provided actual cat motion capture. And even though it was really funny to look at the videos, those poor cats being dressed as motion capture artists, we felt that the freedom that allows the keyframe animation, and also having a lot of very specific situations in the game, that it would be very dangerous to ask an actual real cat to reproduce. We really kept this and the whole project with just manual animation.” Importantly, the developers very much did not set out to make a cat simulator. The cat-like behavior helps the player to feel immersed, but is there to help drive the story first and foremost.

Even though the main inspiration for Stray was Kowloon Walled City, the team also played around with other influences such as Blade Runner or even the endless amount of cat videos on the internet. The team was purposeful about allowing time for inspiration to write a cat-centered story, letting new environments, new characters and new side quests inspire the main storyline.

More than twenty cats were involved in the creation of the game, but the developers expressed that their own cats were the biggest inspiration. When it comes to the animation and design of the game’s feline protagonist, three cats were highly involved. For the animations, Miko drew inspiration from his cat Oscar, a sphynx cat who frequently came with him to the BlueTwelve office. Miko studied his physical movements, from jumping to running and even the twitching of his ears. Conveniently, Oscar is a hairless sphynx cat, which made it easy for Miko to study his movements and muscles. However, the team expressed they were not aiming for extreme muscle precise animation.

The cat’s overall appearance is based on Murtaugh, also nicknamed The Boss, an actual stray cat Viv and Koola found underneath a car in Montpellier. They ended up adopting the cat and named him after Roger Murtaugh from the Lethal Weapon series. The BlueTwelve co-founders created many versions of the main character, but eventually opted for a ginger tabby lookalike of Murtaugh. When designing the protagonist, they intentionally went for an interesting and expressive vibe over realism, choosing a more animated style – a curious face with big eyes – instead of a hyper-realistic cat.

Cat Lala was hired to produce the meows and purrs for the game. Together with Jun, the third office cat, Oscar and Murtaugh reminded the developers of their typical cat-like traits. “Having cats in the office is really a constant reminder of their personality. You know, when they step on the power button just when you’re about to save your work on the computer, or when they start singing when you have an important call… I think that was a constant reminder of how playful they can be and how interesting it would be to have the personality of cats in the game and have some situations that make fun of the inhabitants of the city.” When their own office cats started reacting to the purrs, and the movements of the cat on screen, the developers knew they were on the right track.

Over the span of a few years, the team went from 5 to 16 members, eventually growing to 24 team members and three additional contractors for software engineering during the peak of production. Though the scope of the game changed a few times as it became bigger, the team was very adamant about focusing on the features and moments that were important to them, such as the story and the immersive experience, rather than try to create an open-world game worth hundreds of hours of gameplay. Reportedly, Annapurna Interactive provided useful feedback in every stage of development, from conception, through pre-production, up until release, all without disturbing BlueTwelve’s creative freedom, which the studio greatly appreciated.

In June 2020, the game was officially announced during the first Playstation 5 showcase event as ‘Stray’, said to be released in 2021. It immediately received a lot of attention due to its unique concept. The team didn’t expect all this excitement from just the reveal, but it left them extremely thrilled to see all the people, especially the cat owners, being so interested in Stray. It’s ultimately what they were aiming for, but being a small team and Stray being their very first game, it also pressured them to create an experience that’s as polished and detailed as possible.

They decided to focus on the production and deliberately waited to promote and communicate about the development process. In July 2021, at the Annapurna Interactive Showcase, gameplay footage was shown in a second trailer. It was also announced that Stray’s release date was delayed to early 2022, to ensure the development team’s well-being and to not have to compromise on the game’s quality. Later, this release date was delayed twice more, becoming ‘mid-year 2022’ and eventually ‘July 2022’.

In the end, the game’s delay was more than worth it. Even before release, the game topped Steam’s wishlist charts. On July 19th 2022, Stray launched for PS4, PS5 and PC, and immediately broke Annapurna Interactive’s record for concurrent Steam players upon release, with over 62,000 players, making it a massive hit. Stray also became Steam’s highest user-rated game of the year and even went viral, partially because of videos of cats watching their owners play Stray.

The reviews for Stray were very positive. The animations and art direction were praised, as was the realistic cat-like behavior and the use of environmental storytelling. Critics were divided on the combat and stealth sequences: some found them tense and exciting, others a bit tiring and boring.

In Japan some players were critical about scenes where the cat main character was hurt or being attacked. They said that ‘those with no stomach for horror or the grotesque should be warned’, suggesting the cruel depictions of dead bodies, and the posts blew up online. Many other players confirmed the reviews were blown out of proportion. Even when the cat gets overwhelmed by Zurk attacks, the screen will turn a bright red when the cat becomes dangerously ‘hurt’, falling over without showing any actual blood. Therefore, Stray received a CERO B, for ages 12 and older, rating in Japan.

Upon Stray’s release, Annapurna partnered with UK’s Charity Cats Protection and the Nebraska Humane Society: two charities to raise money for homeless animals. Players could win a copy of Stray by donating a small sum or by fundraising via streaming. BlueTwelve expressed having learned a lot from developing Stray: firstly, how to build a team around a specific game project. Playing as a cat posed a whole new set of development challenges no one could have prepared them for, like the animations, the specific mechanics, the vertical level design, the coding and so on. Moreover, much of the developers’ knowledge they acquired on previous projects, had to actively be relearned and reinvented for Stray, seeing as many traditional ‘development rules’ didn’t apply to this game. For example: the team had a very high standard for what the visuals had to look like, so they had to reinvent their iterative processor to have backgrounds with a certain level of detail.

But what’s next for Stray and BlueTwelve Studio? Some fans have expressed the need for cat customization, and some modders have even taken it upon themselves to mod players’ pets into their games, crafting custom downloadable cat textures. Though the team admits to having discussed the option during development, there are currently no signs of customization DLC. The team also preferred a unique and recognizable character, which would fall to the wayside with the introduction of cat customization. As of today, it’s unclear what the team’s next step will be. Just before release, BlueTwelve did say the studio’s future endeavors depend on how Stray would be received.

It really depends a lot on how players will enjoy the game and will react. We’re still trying to finish, and have the best-polished experience as possible. So we try not to extrapolate too much on what is going to happen next. Depending on the feedback we have, we might think very differently about the future. So this being our first game, we feel that the best course is to see what happens and react to this.

BlueTwelve Studio