Buy Mainframe Defenders PC Key

Looking for a cheap Mainframe Defenders key? As of 6 Aug 2026 the lowest offer is $0.59 at Steam, picked from 14 offers across 9 stores. Keyshops start at $0.92, official stores at $0.59. 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. 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: 25 Feb 2020
Synthetic Domain
Metacritic:
tbd tbd
Steam:
Very Positive (639)
Buy in Official Store:
-90%
$0.59
Buy in Keyshops:
-83%
$0.92
See price history

Official Stores (2)

DRM:
Steam
Mainframe Defenders
Windows
+2
13h ago
DRM:
Steam
Ends in 1 week
Steam
$5.99 $0.59
Ends in 1 week
-90%
GOG.com
Mainframe Defenders
Windows
+2
4d ago
DRM:
GOG
GOG.com
$5.99 $0.59
-90%

Keyshops (12)

DRM:
Mainframe Defenders (PC) Steam Key GLOBAL
5.0
Windows
+2
8h ago
DRM:
Steam
Eneba
$5.65 ~$0.92
-83%
-10% with XDD10copy
-10% with XDD10copy
G2Play
Mainframe Defenders Steam CD Key
Windows
+2
6h ago
DRM:
Steam
G2Play
$5.65 ~$2.36
-58%
-8% with XD8DEALScopy
-8% with XD8DEALScopy
Kinguin
Mainframe Defenders Steam CD Key
Windows
+2
7h ago
DRM:
Steam
Kinguin
$5.65 ~$2.36
-58%
-8% with XD8DEALScopy
-8% with XD8DEALScopy
Driffle
Mainframe Defenders (Global) (PC / Linux) - Steam - Digital Key
Windows
+2
1d ago
DRM:
Steam
Driffle
$2.76 $2.59
-6%
-6% with XDDEALS6copy
-6% with XDDEALS6copy
Mainframe Defenders (PC) Gog.com Key GLOBAL
5.0
Windows
+2
8h ago
DRM:
GOG
Eneba
$5.65 ~$2.82
-50%
-10% with XDD10copy
-10% with XDD10copy
G2Play
Mainframe Defenders GOG CD Key
Windows
+2
6h ago
DRM:
GOG
G2Play
$5.65 ~$2.83
-49%
-8% with XD8DEALScopy
-8% with XD8DEALScopy
Kinguin
Mainframe Defenders GOG CD Key
Windows
+2
7h ago
DRM:
GOG
Kinguin
$5.65 ~$2.83
-49%
-8% with XD8DEALScopy
-8% with XD8DEALScopy

About Mainframe Defenders

Mainframe Defenders - about the game
Lead a squad of four prototypes through the virus-infected Stargazer research complex in this tactical retrofuturistic strategy game. Repel enemy assaults, destroy unit fabricators, download data, and clear infected nodes to reach the deepest mainframe defenses. Combine items with limitations and drawbacks to craft potent squad builds, then unleash tactics like overheating foes, corroding armor, absorbing hits, or applying debuffs. Enemies counter specific approaches with their squad roles, forcing smart target choices amid procedural levels blending hand-made rooms and random generation. Missions vary objectives and conditions for replayable challenges. Progression unlocks new units with unique upgrades and loadouts, plus fresh items to refine strategies-perfect for indie strategy and RPG fans who thrive on adaptive squad-building and tactical depth.

MAINFRAME DEFENDERS

Tactical retrofuturistic strategy game. A computer virus has infiltrated the "Stargazer" research complex. Most of the robotic units are controlled by the virus. Lead a squad of 4 prototypes on a mission to defend complex mainframe. You'll have to repel assaults, destroy unit fabricators, download valuable data, clear infected nodes, and do more on your way to the deepest parts of the complex. Work with item limitations and drawbacks to build powerful combinations. Destroy your enemies with diverse tactics: overheat them, melt with corrosion, absorb damage, and return fire. But don't rely on a single strategy too much - enemies might have a way to counter it. But above everything else: defend the Mainframe!

* RETRO STYLE: Graphics, inspired by 80s terminal PC with hybrid synthwave soundtrack.

* DIVERSE TACTICS: Cook enemy robots to death, bury them under your bullets, eliminate with a single powerful shot, or render your opponents useless with debuffs - this game is designed with a lot of viable strategies in mind.

* BUILD YOUR SQUAD: Similar to how in card games you have to build your deck, in Mainframe Defenders you have to combine different items with unique abilities, to create an unstoppable squad. Work with item drawbacks or double down on them, creating flawed, yet powerful build!

* UNIQUE ENEMIES: Enemy squad won't sit idle, though. Each unit has its own role in the squad and designed to counter certain strategies. Pick your targets wisely, or you will lose.

* PROCEDURAL LEVELS: Hand-made rooms are combined with procedural generation to create random levels. Missions have differing objectives, combined with unique mission conditions. Will you accept the challenge or avoid the unknown and risk falling behind?

* PROGRESSION SYSTEM: Victory or defeat, the game is not over yet! Unlock new units, each with a unique set of upgrades and load-outs. Unlock new items to bolster your new strategies.


Join our Discord to stay informed about updates for Mainframe Defenders. There you can share feedback and suggestions, as well as chat with our team about the next project_

Interface:
GermanEnglishSpanish - SpainFrenchHungarianItalianJapaneseKoreanPolishPortuguese - PortugalPortuguese - BrazilRussianSimplified Chinese
Subtitles:
GermanEnglishSpanish - SpainFrenchHungarianItalianJapaneseKoreanPolishPortuguese - PortugalPortuguese - BrazilRussianSimplified Chinese

Age rating

Unavailable
Metacritic:
tbd tbd
Steam:
Very Positive (639)

Minimum:

  • Processor: Intel Celeron
  • Memory: 2048 MB RAM
  • DirectX: Version 10
  • Storage: 200 MB available space
  • Additional Notes: Requires a 64-bit processor and operating system

Recommended:

  • Additional Notes: Requires a 64-bit processor and operating system

Minimum:

  • OS: Ubuntu 14.04 LTS
  • Processor: Intel Celeron
  • Memory: 2048 MB RAM
  • Storage: 200 MB available space
  • Additional Notes: Requires a 64-bit processor and operating system

Recommended:

  • Additional Notes: Requires a 64-bit processor and operating system
Historical low
Price history from official stores
$0.59
Steam
today
Price history from keyshops
$0.23
Gameseal
6 months ago

FAQ

9 questions

Before you start looking for a cheap Mainframe Defenders PC key, check the essentials. Developed by Synthetic Domain. Published by Synthetic Domain. PC released date: 25 Feb 2020. Genres: Strategy, Indie, RPG. Categories: Family Sharing, Steam Trading Cards, Single-player, Steam Achievements.

Q

Where to buy a cheap Mainframe Defenders Steam key or CD key?

Using our price comparison and verified discount codes, you can buy a Mainframe Defenders key for as low as $0.59. This deal is available at Steam 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 Mainframe Defenders price on PC. Check the Mainframe Defenders price history to buy at the best moment.

As of our last update (we refresh Steam pricing multiple times a day), the Mainframe Defenders Steam price is $0.59. 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 Mainframe Defenders on sale even outside seasonal promotions. We currently detect 14 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, Mainframe Defenders is not currently available on GeForce NOW. You will need to run it locally on your PC. Browse games available on GeForce NOW.

The spread between offers was wide: from $0.23 to $7.30. The cheapest offer came most often from Kinguin: 71 of 168 days with data. Half of all readings fell between $0.44 and $1.81. We have recorded offers from 10 stores in total, and from 4 in the most recent reading.

Yes. Mainframe Defenders has an official page on the Steam Store. You can also buy a Mainframe Defenders Steam key from third-party sellers. Our price comparison currently includes 7 offers with Steam DRM. Pick one to ensure your Mainframe Defenders download happens on Valve's platform.

Yes, with minor tweaks. Mainframe Defenders is Steam Deck Playable - it works after small adjustments like selecting a Proton version or using the touchscreen for tiny launcher text. You can play Mainframe Defenders on Steam Deck.

According to our data Mainframe Defenders 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 Mainframe Defenders 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 Mainframe Defenders

1 Steam Steam Official
-90% $0.59
2 GOG.com GOG.com Official
-90% $0.59
3 Eneba Eneba Keyshop
-83% $0.92
4 G2Play G2Play Keyshop
-58% $2.36
5 Kinguin Kinguin Keyshop
-58% $2.36

Want to buy at the best moment? Set a price alert on XD.deals and get notified when Mainframe Defenders hits its next historical low.

Create Alert
Join our Discord
Get instant help from our community and stay updated on the latest deals
Set Price Alerts
Get notified by email when game prices drop to your target
Create Free Account
Unlock wishlists, price alerts, and Steam sync