PEAK: The Co-op Climbing Game Born in a Seoul Game Jam That Sold 10 Million
Two small studios, one from Seattle and one from Stockholm, spent a month in Seoul making a 'learning experience'. It became one of 2025's biggest games. The story of PEAK, its scouts, its Scoutmaster and the Final Ascent.
Most games that sell ten million copies begin with a business plan. PEAK began with a plane ticket. In February 2025, two small studios gathered in Seoul for a month-long game jam (a short, intense period of making a game from scratch, usually just for fun or practice). They planned it as a small experiment, what they called a "learning experience".
That experiment became PEAK, a co-op climbing game by Aggro Crab and Landfall. It launched on Steam for Windows on 16 June 2025 priced at $7.99, sold 100,000 copies in 24 hours, 1 million in a week and more than 10 million by mid-August 2025. In August 2026 it received its biggest update yet, The Final Ascent.
Two studios, one mountain
The two developers are an unusual match. Aggro Crab, founded in 2019 in Seattle by Nick Kaman and Caelan Pollock, is a team of about 13 best known for the roguelike Going Under (2020) and the colourful crab soulslike Another Crab's Treasure (2024). Landfall, founded in Stockholm in 2015, makes physics comedy: Clustertruck, Totally Accurate Battle Simulator and the co-op horror hit Content Warning. It describes itself as a "small studio staying small".
Landfall's history is full of youthful mischief. Two of its key people, Wilhelm Nylund and Philip Westre, released their first game, Air Brawl, in 2014 while they were still in high school. The studio is famous for launching games on April Fools' Day: the free battle royale Totally Accurate Battlegrounds drew about 3 million players in the two days after its 2018 April Fools' release, and Content Warning arrived on 1 April 2024, reaching more than 50,000 concurrent players in its first 12 hours and about 2.2 million sales within two months.
Aggro Crab, meanwhile, has a reputation for colour, jokes and outspokenness. In 2022 it publicly criticised its former publisher Team17 over NFT plans, and after PEAK it kept moving, announcing a new co-op game, Crashout Crew, for Windows and Xbox Series X|S in October 2025.
The timing was dramatic. In June 2025, the month PEAK launched, Aggro Crab cancelled its planned Going Under 2 after losing its funding over differences in creative vision. A game made for practice suddenly mattered a great deal.
How PEAK plays
You and up to three friends are Scouts, castaways whose plane has crashed on a mysterious island. The only way off is up. Played in first person with proximity voice chat, the game asks you to climb a mountain that changes every day.
The core is a stamina bar. Climbing drains it, and hunger, injuries, poison, extreme temperature and the weight you carry all shrink it further. Run out and you fall unconscious, and if nobody revives you, you die. Teammates can bring you back with items or at special altars, which means every climb is a negotiation: who carries the food, who goes first, who gets left on the ledge.
The mountain has six biomes, with middle stages that rotate between variants such as the Alpine slopes or the Mesa, until you reach the summit, also called Peak. Levels rotate every 24 hours at 17:00 UTC (02:00 the next day in Korea), so the whole player base faces the same mountain on the same day, and tomorrow there will be a new one. Badges reward feats and unlock cosmetics.
A $7.99 price tag and a perfect storm
PEAK arrived during a wave of cheap, funny co-op games that streamers and friend groups adored, the same wave that carried R.E.P.O. (read our story) and Lethal Company before it (here). Its low price made it an easy group purchase: four friends could buy it for less than one full-price game.
What made it stand out was its tone. Where many co-op hits lean on horror, PEAK is closer to slapstick mountaineering. Falling is funny. Catching a friend's hand at the last second is a triumph. Watching someone eat the wrong mushroom is a story you will tell for weeks.
By the numbers
- 1 month of development in the original Seoul game jam
- $7.99 regular price on Steam
- 100,000+ copies in the first 24 hours
- 1 million+ in the first week, already more than Another Crab's Treasure
- 2 million by day nine, 5 million+ in the first month
- 10 million+ by mid-August 2025
- 82 on Metacritic, with 100% of critics recommending it on OpenCritic
- 6 biomes and 4 players
Updates: from Mesa to the Final Ascent
Aggro Crab and Landfall kept the mountain growing. The Mesa update on 11 August 2025 added the Mesa variant of the Alpine level. The Roots, on 5 November 2025, added a fungal forest variant of the Tropics. Then on 11 August 2026, almost exactly a year after Mesa, The Final Ascent added two more variants, Gloom and The Citadel, in what the studios presented as a major update, followed by bugfixes and maintenance patches.
The game also spread beyond itself. There are official plushies of the player character and of Bing Bong, a fan-favourite item from the game, along with figurines and merchandise. In December 2025, rapper bbno$ played an in-game concert, and in March 2026 a PEAK cosmetic bundle arrived in the Fortnite Item Shop.
The trophy shelf
PEAK won Best Multiplayer Game and Streamer's Choice at the Golden Joystick Awards 2025, Stream Game of the Year at The Streamer Awards 2025 and the "Better With Friends" prize at The Steam Awards 2025. It was nominated for Best Multiplayer Game at The Game Awards 2025 and longlisted at the BAFTA Games Awards 2026.
Why it matters
WGC's take: PEAK is the strongest argument yet for game jams as a business strategy, not just a hobby. Landfall did it with Content Warning, then did it again with PEAK, alongside a partner studio that badly needed a win. Short, focused development keeps ideas small and sharp, and a low price turns a funny idea into something friends buy together on impulse.
The other lesson is about updates. PEAK did not stop at launch. Three content drops in a little over a year gave players a reason to return, and kept the game in streams and group chats long after most jam projects would have been forgotten. A month of making, followed by a year of caring, turned out to be the winning formula.
There is also a Korean footnote worth savouring. One of 2025's most-played Steam games was born in a month of work in Seoul. For a country that has spent years building its own indie scene, it is a nice reminder that the city is already part of the global indie map.
What to play next
PEAK is on Steam for Windows. For another co-op game that started as a jam project and sold in the millions, read about RV There Yet? (here). If you prefer your friends-only chaos with more monsters, R.E.P.O. and Lethal Company are the genre's other giants. And if you want to climb alone, at your own pace, the deckbuilding tower of Slay the Spire 2 is waiting (here).