This product is a brand new and unused Mercury Fallen CD Key for Steam.

Immediately after payment, you will be sent a unique and unused CD Key which can be activated on Steam. You can collect this activation code from our Autokey page.  Simply enter your code into the Steam client (available free from steampowered.com). This will then grant you to a full digital download of the game.

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CJS CD Keys sell brand new CD Keys either taken directly from brand new sealed copies of the game, or sourced directly from world-leading game publishers. We source our keys in bulk directly from leading distributors and publishers, which reduces shipping costs.  This enables us to offer instant online delivery, at extremely competitive pricing.

After you receive your key, you can activate the game on the Steam client (available free from steampowered.com). After you activate the game with the Steam software, you can download the game immediately and instantly.

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Regional Availability

This product key we are selling is sourced directly from the publisher, or an official distributor of the game publisher. The key is completely region free and includes all languages. Region free means that you can activate the product code from anywhere in the world.

About Mercury Fallen:

About This Game

Awaken. Rebuild. Explore.

After a long journey to a distant planet, your colonists were supposed to wake up and begin building their new home. But something went wrong. Their stasis capsules malfunctioned, and when they finally awakened, the underground facility they were meant to inhabit has fallen into ruin.

Now, it's up to you to restore the base, manage resources, and expand across the planet’s surface—all while uncovering the secrets of this alien world and ensuring your colony thrives.

Mercury Fallen is a self-paced sci-fi colony management experience with a focus on exploration, expansion, and story-driven progression. Deconstruct the remnants of an abandoned facility, construct new rooms, conduct research, and grow your colony both underground and across the planet’s surface.

Tear down the ruins, scavenge resources, and transform the underground into a thriving colony. Design essential rooms, power systems, and infrastructure to support your growing population.

• Uncover additional colonists, robots, and discoveries hidden in collapsed sections of the Mercury Facility.

• Build and manage power and water resources to sustain your growing colony.

Unlock advanced technology, craft vital upgrades, and send colonists on daring expeditions to uncover alien artifacts, lost technology, and the secrets buried beneath the planet’s surface.

• Research technology to unlock new rooms, crafting recipes, crops, and facility upgrades.

•  Discover alien plant life and new resource types to fuel your colony’s expansion.

Expand beyond the underground with surface expeditions and resource extraction.

• Construct vehicles to explore alien terrain and extract rare materials.

• Expand your power network above ground with multiple energy generation methods.

• Send colonists to explore points of interest, uncovering new resources, hidden lore, and lost technology.

Every colonist has a story. Some will thrive, others will struggle—but they all rely on you. Keep them housed, happy, and well-fed while managing their quirks, relationships, and unexpected disasters. As your colony grows, expand your workforce with clones and automated robots to optimize daily operations.

Key Colony Features:

• A Colony That Feels Alive: Colonists have unique quirks, moods, and challenges. Keep them happy, or risk disaster as stress builds and problems arise. Manage colonists’ injuries, ailments, jobs, quirks, and needs to ensure long-term survival.

• Build & Design Essential Spaces: Construct bedrooms, recreation areas, crafting stations, and more to meet the growing needs of your colony.

• Customize your Colonists: Give your settlers unique names, outfits, and equipment, making each colonist truly your own.

• Cultivate Alien and Terrestrial Crops: Grow a variety of terrestrial and alien crops to sustain your colony and fuel advanced production chains.

• Expand Your Workforce: Grow clones and assemble robots to expand your facility population.

• Brace for the Unexpected: React to and prepare for random events, including cave-ins and crop disease.

Procedurally generated worlds ensure a fresh experience each time, while Steam Workshop modding support lets you expand and customize your gameplay. Dynamic events introduce unexpected challenges and opportunities, making each colony feel unique.

Every colony tells a different story. Will yours flourish or fall? With procedurally generated worlds, dynamic challenges, and a blend of underground base-building, planetary exploration, and rich storytelling, Mercury Fallen is an ever-evolving adventure—whether you prefer a laid-back experience or a challenge that keeps you on your toes.