Buy Sigma Theory: Nigeria - Additional Nation PC Key

This content requires the base game: Sigma Theory: Global Cold War

Looking for a cheap Sigma Theory: Nigeria - Additional Nation key? As of 21 Aug 2026 the lowest offer is £0.90 at Yuplay, picked from 8 offers across 8 stores. Keyshops start at £0.90, official stores at £1.99. On PC the keyshop wins on price in most comparisons, but then you are buying a code from a third-party seller, so check the activation region. This game has been cheaper before, on 85% of the days we have data for. A price alert will let you know when the next drop comes. This is an add-on, so you also need the base game to play it. That costs £0.40 today, which puts the pair at £1.30. On PC you buy a key that you activate in Steam or another client, and this is the widest market we track, with more than a quarter of games carrying a keyshop offer.

Release: 19 Feb 2020
Mi-Clos Studio
Metacritic:
tbd tbd
Steam:
Overwhelmingly Negative (7)
Buy in Official Store:
-4%
£1.99
Buy in Keyshops:
-56%
£0.90
In official stores, it was cheaper on 85% of days with data.
See price history

Official Stores (6)

DRM:
Steam
Steam
Gamesplanet UK
Sigma Theory DLC - Nigeria Additional Nation
Windows
+2
28w ago
DRM:
Steam
Gamesplanet UK
£2.09 £1.99
-4%
Gamesplanet FR
Sigma Theory DLC - Nigeria Additional Nation
Windows
+2
14h ago
DRM:
Steam
Gamesplanet FR
£2.14 ~£2.03
-5%
Gamesplanet DE
Sigma Theory DLC - Nigeria Additional Nation
Windows
+2
14h ago
DRM:
Steam
Gamesplanet DE
£2.14 ~£2.03
-5%
Gamesplanet US
Sigma Theory DLC - Nigeria Additional Nation
Windows
+2
15h ago
DRM:
Steam
Gamesplanet US
£2.19 ~£2.08
-5%
Steam
Sigma Theory: Nigeria - Additional Nation
Windows
+2
1w ago
DRM:
Steam
Steam
£2.09
GamersGate
Sigma Theory DLC: Nigeria Additional Nation
Windows
+2
26w ago
DRM:
Steam
GamersGate
£2.09
-10% with XDD10copy
-10% with XDD10copy

Keyshops (2)

DRM:
Steam
Steam
Sigma Theory DLC: Nigeria Additional Nation
5.0
Windows
+2
5d ago
DRM:
Steam
Yuplay
£2.09 £0.90
-56%
-3% with XD3OFFcopy
-3% with XD3OFFcopy
CJS-CDKeys
Sigma Theory: Nigeria - Additional Nation Steam Key (GLOBAL)
Windows
+2
3w ago
DRM:
Steam
CJS-CDKeys
£2.09 £1.76
-15%

About Sigma Theory: Nigeria - Additional Nation

Sigma Theory: Nigeria - Additional Nation - about the game

Sigma Theory: Global Cold War is a turn-based strategy and simulation game set in a near-future scenario where nations compete to achieve technological supremacy through advanced research. Players take on the role of an intelligence agency director tasked with advancing their chosen country's position in a tense global standoff. The core experience blends espionage tactics with diplomatic maneuvering and resource management to push forward critical scientific breakthroughs before rivals can.

Gameplay

The central loop revolves around recruiting and deploying specialized agents to gather intelligence, influence key figures, and conduct covert operations across international locations. Agents possess distinct skills suited to tasks such as seduction, blackmail, or direct confrontation, allowing players to tailor approaches based on mission needs. Relations with numerous non-player characters, including politicians, lobbyists, and armed factions, shift dynamically through choices that can lead to alliances, betrayals, or eliminations.

Progress centers on advancing Sigma Research projects while monitoring a Doomsday Clock that tracks escalating global tensions. Successful operations yield data and resources that accelerate technological development, but missteps risk drawing unwanted attention or triggering conflicts. Field actions often involve navigating urban environments for objectives like target extractions, where agent abilities and environmental factors determine outcomes. Nation-specific traits further shape strategies, providing advantages or restrictions that influence long-term planning.

Game Modes

Two primary modes structure play sessions. Story Mode assigns players to a fixed starting nation with guided narrative elements that emphasize character interactions and sequential objectives. Regular Mode offers greater flexibility, letting players select any available nation from the outset and pursue open-ended goals without scripted constraints. Both modes maintain the same underlying systems for agent deployment and research advancement, though Story Mode incorporates additional dialogue-driven events.

Nations and Agents

Each playable nation brings unique agents, scientists, and a diplomat to the roster, along with a defining trait that alters gameplay priorities. The Nigeria addition introduces four specialized agents named Warrior, Peace, Pure, and Dealer, each bringing distinct capabilities to operations. Two Nigerian scientists contribute to research efforts, while the diplomat facilitates international dealings. Exfiltration missions take place in Abuja, and the nation's trait grants immunity to interference from armed groups, enabling safer focus on other threats and objectives.

Is It Worth Playing?

Sigma Theory suits players who enjoy compact turn-based strategy experiences centered on espionage and political maneuvering rather than large-scale battles or extended campaigns. Its systems reward careful agent assignment and relationship management, with nation choices like Nigeria offering fresh tactical options through specialized personnel and defensive traits. Reception highlights the game's focused scope and intrigue for those drawn to spy-themed simulations, though some note its brevity limits depth for extended sessions. The title remains available on PC with its additional nation content intact, making it a solid option for fans of deliberate, choice-driven strategy without ongoing seasonal updates.

Interface:
GermanEnglishFrenchRussianSimplified Chinese
Audio:
English
Subtitles:
GermanEnglishFrenchRussianSimplified Chinese
Metacritic:
tbd tbd
Steam:
Overwhelmingly Negative (7)

Minimum:

  • Processor: 1, 3 GHz CPU
  • Graphics: NVIDIA GT 440 or AMD Radeon HD 5550 w/ 512 MB
  • Storage: 50 MB available space

Recommended:

  • OS: Windows 10
  • Processor: Dual-core 2Ghz CPU
  • Graphics: DirectX® 10 compliant graphics card
  • DirectX: Version 10
  • Storage: 100 MB available space

Minimum:

  • OS: OS X 10.8.5
  • Processor: Dual Core 2Ghz
  • Graphics: Hardware Accelerated Graphics with dedicated memory
  • Storage: 50 MB available space

Recommended:

  • OS: OS X 10.9.1
  • Processor: Dual-core 2Ghz CPU
  • Graphics: Intel Iris Pro, NVIDIA GTX 660 Ti, or AMD Radeon HD 7870 w/ 1024 MB
  • Storage: 100 MB available space

Minimum:

  • OS: Ubuntu 12.04+
  • Processor: Dual-core 2Ghz CPU
  • Storage: 50 MB available space

Recommended:

  • OS: Ubuntu 12.04+ Desktop only
  • Processor: Dual-core 2Ghz CPU
  • Storage: 100 MB available space
Historical low
Price history from official stores
£1.04
Steam
2 weeks ago
Price history from keyshops
£0.79
Yuplay
3 months ago
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FAQ

9 questions

Before you start looking for a cheap Sigma Theory: Nigeria - Additional Nation PC key, check the essentials. Developed by Mi-Clos Studio. Published by Mi-Clos Studio. PC released date: 19 Feb 2020. Genres: Strategy, Simulation. Categories: Family Sharing, Steam Trading Cards, Steam Workshop, Single-player, Downloadable Content, Steam Achievements, Steam Cloud, Steam Leaderboards.

Q

Where to buy a cheap Sigma Theory: Nigeria - Additional Nation Steam key or CD key?

Using our price comparison and verified discount codes, you can buy a Sigma Theory: Nigeria - Additional Nation key for as low as £0.90. This deal is available at Yuplay and is among the cheapest offers on the market. All keys listed on XD.deals are delivered digitally and eligible for instant download after payment. Prices already include processing fees and applied promo codes, so you always see the lowest Sigma Theory: Nigeria - Additional Nation price on PC. Check the Sigma Theory: Nigeria - Additional Nation price history to buy at the best moment.

As of our last update (we refresh Steam pricing multiple times a day), the Sigma Theory: Nigeria - Additional Nation Steam price is £2.09. You can save an extra ~6% by paying with a discounted Steam gift card.

Our price tracker covers both official retailers and key marketplaces, so you can find Sigma Theory: Nigeria - Additional Nation on sale even outside seasonal promotions. We currently detect 8 active offers from official stores and keyshops. Check the table above, compare against the historical low, and set an alert so you never miss the next price drop.

Based on our data, Sigma Theory: Nigeria - Additional Nation is not currently available on GeForce NOW. You will need to run it locally on your PC. Browse games available on GeForce NOW.

The cheapest offer came most often from Yuplay: 78 of 127 days with data. The current price is high against its own history: it was cheaper on 85% of days with data. The price reached its historical low on only 1 day out of 127 days with data. We have recorded offers from 8 stores in total, and from 1 in the most recent reading.

Yes. Sigma Theory: Nigeria - Additional Nation has an official page on the Steam Store. You can also buy a Sigma Theory: Nigeria - Additional Nation Steam key from third-party sellers. Our price comparison currently includes 8 offers with Steam DRM. Pick one to ensure your Sigma Theory: Nigeria - Additional Nation download happens on Valve's platform.

Not at this time. Valve marks Sigma Theory: Nigeria - Additional Nation as Unsupported on Steam Deck. Keep an eye on XD.deals - we track Proton updates and community fixes. Browse games that are Steam Deck Verified or Steam Deck Playable.

According to our data Sigma Theory: Nigeria - Additional Nation is not currently available on PC Game Pass, EA Play or Ubisoft+. We are still filling in the catalogues of these services, so it is worth confirming the status at the source before you decide. If you are buying, XD.deals will help you find the lowest price.

No - XD.deals is not a store. We are a price-comparison service that tracks the best Sigma Theory: Nigeria - Additional Nation deals across official stores and verified keyshops. Click "Go to Store" next to any offer and you will be redirected to the retailer's website to complete your purchase.

Best prices for Sigma Theory: Nigeria - Additional Nation

1 Yuplay Yuplay Keyshop
-56% £0.90
2 CJS-CDKeys CJS-CDKeys Keyshop
-15% £1.76
3 Gamesplanet UK Gamesplanet UK Official
-4% £1.99
4 Gamesplanet FR Gamesplanet FR Official
-5% £2.03
5 Gamesplanet DE Gamesplanet DE Official
-5% £2.03

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