Calcium Contract

A first-person shooter that lets you rewind your mistakes

Igor Aleksandrowicz · Released Oct 17, 2023

Reviews: Very Positive; 92% of 148
Recent reviews: Not enough recent
Players: 1; daily peak, Oct 28, 2026
Steam Deck: Verified
Last update on Steam: 1 year ago; Mar 14, 2025
Minimum PC: DirectX 11 GPU; 2 GB RAM · 0.3 GB disk; Full requirements

What is Calcium Contract?

This single-player shooter sends you up an island mountain to kill a serpentine creature that refuses to die. You fight through more than twenty levels using the Calcium Order's weapons against enemies, some of which manipulate others. A separate score-attack mode, Eternal Harvest, has procedurally generated levels that rebuild during play and optional curses that raise both difficulty and score.

For you if...

+you prefer short campaigns over lengthy adventures
+you like colorful, surreal settings rather than realistic battlefields

Not for you if...

−you want cooperative play or competitive multiplayer
−you prefer slow-paced combat with little pressure

What players say

92% of 148 reviews are positive

Players praise the level design, weapon feel, and music. Less enthusiastic players find its Doom-like combat less compelling than other retro shooters.

Screenshots and trailer

Calcium Contract system requirements

Minimum: DirectX 11 GPU, 2 GB RAM, 0.3 GB of disk space.

As published by the developer.

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Minimum

OS: Windows 10 64-bit or later
Processor: 2.5 GHz
Graphics: Directx 11 support
Memory: 2 GB RAM
Storage: 300 MB available space
DirectX: Version 11

Does Calcium Contract have co-op or multiplayer?

No: single-player only, no multiplayer modes declared.

Single-player

Does Calcium Contract run on Steam Deck?

Verified Yes, Verified by Valve: it works on Steam Deck out of the box.

All functionality is accessible with the default controller configuration
Shows Steam Deck controller icons
In-game text is legible on Steam Deck
Default graphics settings perform well on Steam Deck

PC version details

DRM: None declared on Steam
Controller: Full controller support
Platforms: Windows
Achievements: 30
Steam features: Cloud saves, Family Sharing
Languages: Full audio: English, Czech, Polish, French, Italian, German, Spanish - Spain, Portuguese - Brazil, Simplified Chinese.

Does Calcium Contract use AI-generated content?

No AI-generated content is disclosed on the game's Steam page.

Self-reported by the developer under Steam rules: it covers AI content that ships in the game, not tools used to make it. Steam page checked on Oct 27, 2026. How to filter AI games on Steam