Rain World is a 2017 survival-platform video game created by an independent studio called Videocult and published by Adult Swim Games and Akupara Games. It was released for PlayStation 4 and Windows in March 2017 and for Nintendo Switch in December 2018. The player controls a character called a "slugcat," which looks like a mix between a cat and a slug. The slugcat must survive in a run-down and dangerous environment. It moves through the remains of an ancient industrial civilization while searching for its lost family. The slugcat uses objects as weapons to avoid dangerous predators, finds food, and tries to reach safe places to hibernate before heavy rain arrives. The game can be played alone or with multiple players, and it includes a sandbox mode.

Development of Rain World began in 2011 and took over six years to complete. The game was funded through Kickstarter and created by a two-person team. The developers aimed to create a realistic ecosystem where creatures move independently of the player and explore the environment constantly. The game uses automatically generated movements in real time and tells its story through the environment. The soundtrack includes low-fi and electronic music that changes based on the game's events. Players receive little direct instruction, helping them feel like a small animal learning to survive in a complex world without fully understanding its rules.

Rain World received mixed reviews from critics. Some praised its art style and smooth animations, but others criticized its difficulty, checkpoint system, and controls. These issues were improved in later updates. The game was nominated for awards and gained a large fan base and a strong modding community. A downloadable content pack called Rain World: Downpour, based on a popular community-created mod, was released for Windows in January 2023 and for consoles in July 2023. This pack added five slugcat characters with special abilities and received positive reviews. A second content pack, Rain World: The Watcher, was released for Windows in March 2025 and for consoles in September 2025.

Gameplay

Rain World is a two-dimensional (2D) survival-platformer game that uses procedural animation, a technique that creates unique animations in real-time, unlike traditional methods. Players control a slugcat, an animal similar to a cat and a slug. In this nonlinear game, the slugcat freely explores individual screens by squeezing through pipes or walking. Some screens contain creatures that move around the area. The slugcat can jump, swim, and climb poles to avoid enemies while searching for food, which must be eaten to hibernate in limited, safe rooms. The slugcat uses spears and debris to defend itself from predators in a ruined, industrial environment. Hibernation spots act as checkpoints where the slugcat returns after dying; if it fails to reach a shelter before the cycle ends, rain will fall, killing the slugcat in a flood.

When the slugcat dies, it loses one "karma" level, which is earned by hibernating. The slugcat can avoid losing karma by eating a yellow "karma flower." The flower appears in specific locations and is replanted wherever the slugcat dies after consuming it. To progress through gates at the borders of the game's 12 regions, the slugcat must reach a specific karma level.

Predators in the game include camouflaged carnivorous plants, large gas-producing vultures, and colorful Komodo dragon-like lizards. Some creatures are friendly but can be provoked, such as "scavengers," which move like the slugcat and carry explosive spears. Many enemies can kill the slugcat in one attack. Some creatures have variations, like differently colored lizards with unique traits. All creatures move independently, sometimes fighting or hunting each other. The slugcat can carry two items and uses its right hand first when throwing, swapping items if needed. Some foods provide special effects, such as slowing down time.

Players can choose to play as the Monk or Hunter slugcats. As the Monk, creatures are less aggressive, and the slugcat needs less food to hibernate. The Hunter, a carnivore with a larger appetite, must hunt bigger creatures and can carry extra spears. Other game modes include a multiplayer arena where up to four players battle and a sandbox mode where players freely interact with objects and creatures.

Rain World’s post-apocalyptic setting shows ecological disaster and is drawn in pixel art. The story is told through the environment, dreams during hibernation, and holograms from a worm-like creature that monitors the slugcat. The game gives little guidance, except for the worm creature, which points toward food and story events. This help becomes less frequent as the game progresses. Players can view an in-game map to track their exploration.

Rain World has two downloadable content (DLC) packs. The first, Downpour, triples the game’s world size and adds five new slugcats and ten new regions, separate from the original game. Each slugcat has unique abilities. The Artificer can jump twice midair and create explosives. The Spearmaster produces endless spears but only gains food by piercing other creatures. The Rivulet, a semiaquatic slugcat, moves more quickly but deals with more frequent rain. The Gourmand needs large amounts of food but has a crafting system. The Saint can grapple objects with its tongue for mobility but cannot throw spears and is prone to freezing.

Downpour also adds three game modes: Safari mode lets players watch the ecosystem and control any creature. Challenge mode includes 70 scored challenges with set goals. Expedition offers random missions that reward experience points. Downpour’s release included local cooperative multiplayer and the free Rain World Remix upgrade, which added accessibility options, difficulty customization, and modding support.

The second DLC, The Watcher, adds new regions, creatures, and the Watcher slugcat.

Plot

A family of slugcats is caught in the rain. Two of their children, including the player's slugcat, are separated from the family as they are carried into the remains of an old, abandoned industrial civilization.

Later, the slugcat finds Five Pebbles, a very large, infected, extremely smart, and partly living artificial intelligence known as an "iterator." After climbing above the clouds and moving through Five Pebbles' large structure, the slugcat meets a representation of Five Pebbles. Five Pebbles explains that, like all living things, the slugcat is part of a cycle of death and rebirth. He suggests the slugcat wishes to end this cycle and directs it to a place where it can escape it. Following this guidance, the slugcat travels underground and enters the "Void Sea," a body of "Void Fluid," where it can "ascend."

More details about the setting are found by giving pearls to a damaged iterator named Looks to the Moon, whose structure collapsed and sank into the shoreline. The pearls record religious, cultural, and historical information about the ancient civilization and what happened after they disappeared.

The Hunter's story is a prequel. It begins with a pearl, a green "neuron fly," and a limit of 20 cycles before the Hunter can permanently die from sickness. The slugcat travels to find a comatose Looks to the Moon and revives her with the neuron fly. When Moon reads the pearl, it reveals the Hunter was sent by an iterator named No Significant Harassment.

Downpour's individual stories, though presented out of order in the game, are listed below in chronological order.

• Five Pebbles plans to destroy himself to ascend, but he uses too much water shared with Looks to the Moon. Moon interrupts him, causing the experiment to fail and infecting his structure. This leads Five Pebbles to stop communicating with the local iterator group. Seven Red Suns sends the Spearmaster to deliver a pearl ordering Five Pebbles to stop using water. The message is refused, and the slugcat is expelled. Moon rewrites the pearl and orders the Spearmaster to take it to a communications array. Moon's message announces her upcoming collapse.
• The Artificer witnesses its children being killed by primate-like scavengers. Finding Five Pebbles, he sees value in the slugcat and sends it to eliminate the scavengers who have taken over the city on his structure. The Artificer kills the scavengers and defeats their leader.
• The Gourmand's story happens after the Hunter's. Finding Five Pebbles, he concludes the slugcat does not want to ascend. He unlocks a gate to a slugcat colony and asks the Gourmand to stop other slugcats from meeting him.
• The Rivulet's story takes place after the original game's story. The Rivulet, a partly water-based slugcat, must survive through short rain cycles. Eventually, the slugcat enters Five Pebbles' infected, nearly broken complex and takes the "rarefaction cell," which provides power. Without the cell, Five Pebbles accepts his death and asks the slugcat to give the cell to Moon. By moving through Moon's submerged structure, the slugcat activates the cell, restoring Moon's functions. She sends a message to the iterator group, announcing her revival.
• Far in the future, after Five Pebbles collapsed and rain changed to fluctuating blizzards, the Saint emerges from the Void Sea but wakes on the surface. The slugcat explores to visit "Echoes," the spirits of the ancient civilization who entered the Void Sea but failed to ascend. Eventually, the Saint gains the ability to help creatures ascend. It tries to enter the Void Sea but is sent to the hell-like "Rubicon." The slugcat roams and finds the Void Sea again. Wings grow from the Saint, resembling an Echo's, and it wakes on the surface once more.

Development and release

Rain World was created by Videocult, a small team led by Joar Jakobsson and James Therrien, who is also known as James Primate. Jakobsson worked as the artist, designer, and programmer, while Primate created the game's music, managed the studio's business, and designed levels. This was Primate's first time making a video game. Before working on Rain World, Jakobsson was a graphic designer in Sweden and a new video game developer who learned how to animate characters on his own. He had no experience in the video game industry and had played few games when he started developing Rain World in 2011. A friend encouraged Jakobsson to explore the idea of procedural animation, which is a method of creating movement automatically. He designed an animal and shared updates about the game on his YouTube channel. One viewer called the creature a "slugcat." Jakobsson was interested in abandoned places and what they reveal about the people who lived there. He was inspired by his time as an exchange student in Seoul, South Korea, and wanted to show the life of a rat in Manhattan who survives in a subway but does not understand why the subway exists. In 2012, Primate discovered Rain World on an online forum for indie games. He shared 12 music tracks with Jakobsson after having a nightmare where the game had poor music.

"I wasn't ready for any of this! I had never made a video game before, and I was a graphic design student who was learning everything as I went along!"

Rain World was originally planned as a game where players would hunt one type of prey while avoiding larger predators in a single room. However, the game changed direction as it developed, taking many unexpected turns, but it kept the idea of the slugcat and the setting of a "dirty, wet industrial environment." Jakobsson and Primate wanted players to feel close to understanding the game's setting without fully grasping it. Jakobsson did not plan for the game's extreme difficulty, which he said was a key part of the game's identity.

Jakobsson focused on making art that worked well with the game's design, seeing programming as a tool to achieve goals. Rain World's enemies were made to act unpredictably, living their own lives by hunting and surviving instead of being obstacles for players. Enemies move without fixed paths, and during playtests before the game's release, developers noticed that players' interest in the game changed based on how enemies behaved. Primate wanted enemies to act like real animals in an ecosystem, making players feel empathy for them. Jakobsson explained that the creatures in the game "are also individuals that can learn to recognize you." He used this idea when designing scavengers, who start distrustful of the slugcat but may ally with it if the slugcat helps in battles or gives pearls. The slugcat is meant to avoid fights and survive by hiding or fleeing. To make Rain World different from Metroidvania games, the team emphasized the slugcat's weakness, avoiding the usual idea of players becoming stronger over time. Except for a worm creature and a tutorial, players are not guided and must learn through trial and error.

Procedural animation was important for creating Rain World's natural and "believable" world. It allowed the game's artificial intelligence to make unexpected actions, like creatures looking "frustrated" when failing to catch the slugcat. The game was first written in the Lingo programming language but later switched to C# with its own game engine. Jakobsson designed levels by hand using a standalone level editor. The editor adds repeated elements, like plants and chains, to maps and combines shadows. At one point, the original version of Rain World was planned to include a multiplayer mode with separate story and custom modes. The team raised money through Kickstarter in early 2014 and quickly met their goal. The game was approved by Adult Swim Games and released in 2015. By early 2015, the team switched to the Unity game engine and shared a test version with Kickstarter backers. A seven-minute trailer was released by the end of the year.

Although Rain World's soundtrack was intended to be chiptune, Primate felt that "arcade sounds and retro ideas" did not match the game's natural feel. Instead, he aimed for a "moody, immersive atmosphere." The final soundtrack was low-fi and electronic. He and his music partner, Lydia Esrig, used recordings of city sounds, trash, and metal for the soundtrack and effects. Primate wanted the music to match the game's mix of industrial, science fiction, jungle, and architectural styles.

With little dialogue or narration, Rain World's story was partly told through its soundtrack to help with environmental storytelling. The game starts with simple drum sounds showing the slugcat's fear and hunger before moving to new areas. Rain World has 3.5 hours of music across 160 tracks. When the slugcat is chased, between eight and twelve tracks play at once to create atmosphere and respond to the slugcat's situation, which Primate calls "threat music." While the creatures in Rain World are like the slugcat, the heavy rain was designed to represent "oblivion incarnate," a danger no creature can survive. To show this, different rainstorm sounds layer up as the rain gets stronger. The storm's peak includes pipe organs, creating a "powerful, dramatic feeling."

Videocult shared updates about the game's development in early 2016 and posted another trailer on December 5. Rain World's animation became popular online before its release and was praised by IGN for its "smooth character movements." Primate said this popularity was partly due to GIFs, with one Twitter post shared over 15,000 times. A final trailer was posted on March 8, 2017, revealing the game's release date. Adult Swim Games published Rain World on March 28 for PlayStation 4 and Windows. Reviews compared Rain World's design to other games, including the difficulty of Super Meat Boy (2010), the environment and music of Fez (2012), and the puzzle-platforming of Metroid and Oddworld.

In April 2017, the game received an update to slightly reduce its difficulty. A major update was planned for later that year, including a local multiplayer mode with over 50 rooms and new characters like the Monk and Hunter. The update was released in beta in November for Windows and officially on December 11, 2017. It was also released for PlayStation 4 on December 21, 2018. In January 2018, after rumors, Rain World was released for the Nintendo Switch in the United States on December 13 and in Europe on December 27. A physical version for PlayStation 4 was released later that month. In August 2025, the game was added to the Xbox Game Pass.

In January 2022, due to disagreements with

Reception

The game received mixed reviews when it was first released, according to review websites Metacritic and OpenCritic. Critics were divided, with 43% recommending it. Video game journalists praised the game's art design but criticized its gameplay mechanics, including unavoidable deaths, difficult controls, and time-consuming hibernation requirements.

Despite these challenges, the game gained a dedicated fanbase and a large modding community. The DLC "Downpour," created by players, was well-received by critics and helped increase the game's popularity. According to journalist Simon Carless, "Downpour" contributed to the game's status as a cult hit. It sold 182,000 units on Steam around its release and 280,000 units between March 2022 and February 2023.

Reviewers found the gameplay frustrating, often leading to a lack of motivation. The game's sudden deaths, infrequent checkpoints, repetitive tasks, harsh weather, unpredictable enemy movements, and clumsy controls made it difficult to enjoy. IGN noted that while individual elements were "tough but fair," the combination made the game feel unfair. Game Informer acknowledged the game's attempt to simulate the slugcat's struggle but said the lack of support and poor controls made it hard to complete. Reviewers grew tired of repeatedly navigating rooms with enemies after each death, which reduced their interest in exploring. Polygon's reviewer described feeling defeated after losing progress, while critics criticized the slugcat's awkward animations and throwing mechanics, which caused unnecessary deaths. Rock, Paper, Shotgun compared the game's instructions for throwing to a "bizarre legal document."

Some reviewers did not finish the game, saying it was too difficult for most players. Paste compared the controls to those of Devil May Cry, which required precise movements and would frustrate even experienced gamers. Rock, Paper, Shotgun called the game's checkpoint system among the worst in modern platformers, and GameSpot said the requirement to achieve a positive hibernate-to-death ratio felt disrespectful of players' time. IGN argued that forcing players to repeat areas repeatedly was "antithetical" to the game's goal of rewarding exploration. However, PC Gamer's reviewer saw the game's controls as thematically appropriate, calling the experience "thrilling" and saying learning from repeated deaths was worthwhile. Paste noted that while the game was "beautiful" and "forward-thinking," it should have been more accessible.

Some critics appreciated the game's unique encounters and the need to learn the environment's rules. Rock, Paper, Shotgun described moments of fear and discovery when encountering new enemies, while GameSpot highlighted creative player strategies, such as using a mouse as a lantern or luring enemies to distract the slugcat. PCGamesN said the game's emphasis on manipulating enemy behavior was exciting. Nintendo World Report praised the unpredictable creature behavior, calling it distinct from typical enemies in other games. Shacknews admired the game's pacing, with quiet moments contrasting intense action.

During development, the game's animations gained attention for their smoothness, which reviewers praised at release. IGN called the slugcat's movements beautiful and responsive, with detailed environments. Eurogamer described the game's dark, sinister atmosphere as elegant, and Kotaku admired the slugcat's "pixellated cuteness" despite gameplay frustrations. Nintendo Life's 2024 review said the visuals were beautiful enough to outweigh the repetitive gameplay, praising the opening cinematic's music and storytelling. Nintendo World Report loved the game's gloomy art style, while Polygon said the limited color palette helped distinguish characters from the environment.

Some critics compared the game's aesthetic to Limbo (2010) and Oddworld: Abe's Oddysee (1997), both of which featured dark, engaging worlds and challenging controls. GameSpot said the game effectively portrayed "the cruel indifference of nature," with a surreal, bleak environment similar to BioShock (2007) and Abzû (2016). Paste and Eurogamer noted similarities to Tokyo Jungle (2012), which also explored themes of survival in a post-human world. PCGamesN said the game's simple survival premise evolved into a "sci-fi epic" that made players reflect on life's futility and beauty. Shacknews appreciated the game's soundtrack, which created a sense of loneliness. Eurogamer noted that the game did not achieve the same cultural impact as Hollow Knight (2017), but praised the player's insignificance in the post-apocalyptic world. PC Gamer called the game "daunting but mesmerizing."

The game's harsh and fascinating world left a lasting impression. Some players struggled to fully appreciate it before developers added updates and an easier mode.