For one week only, the strategic action game is available to download from Valve's gaming portal for £12.74, reduced from its usual £14.99 asking price.
Cannon Fodder 3 released in Russia last December. At the time, Codemasters granted developer GFI the licence for a Russia-only release, with no plans for launch in other regions.
A North American and European release followed in February, where it was made available for £19.95 ($25.99) from GamersGate.
The game sees a return of the series' traditional isometric viewpoint, along with 3D visuals, weather effects, day / night cycles, destructible environments and physical water.
It contains cartoon violence set across several locations, with battlefields going beyond Earth and into outer space.
> Read Digital Spy's Cannon Fodder 3 review
> Retro Corner: Cannon Fodder
Watch a trailer for Cannon Fodder 3 below: