Arma: Cold War Assault Remastered

A 2001 classic, modernized, and now open source
Arma: Cold War Assault now runs on a modernized version of its original Poseidon engine: native 64-bit, Windows and Linux, support for ultrawide and high-refresh displays, full game-controller support, and a modern audio and networking stack, while it still plays exactly like the genre-defining original.
The engine is now open source
Bohemia Interactive has released the engine and game source code under the GNU GPL v3.0-or-later, in the spirit of id Software's classic source releases. Anyone can study it, build it, port it, and create with it. Game data and assets remain under Bohemia's Arma Public License Share Alike (APL-SA).
A free Demo is available on Steam if you want to try the engine before buying the full data and campaigns.
The full engine source code is available on GitHub — search for BohemiaInteractive/cwr
What's new in the Remastered engine
Windows & Linux, 64-bit: native cross-platform build (Steam Deck / SteamOS friendly)

Ultrawide & any resolution: aspect-correct field of view; borderless, windowed, or fullscreen; selectable refresh rate and V-Sync

Modern rendering: new OpenGL 3.3 renderer with crisp scalable (TrueType) fonts

Full controller support: gamepad with deadzone/response tuning, plus fully rebindable keyboard, mouse and controller bindings

Modern audio: OpenAL backend with integrated voice chat (VON)

In-game mod manager: enable, order and download community mods from within the game (Bohemia's own catalog), no command line needed

New multiplayer back end: modern master server and in-game server browser (replacing the retired GameSpy service)

Open toolchain for creators: bundled tools for PBO archives, models, terrain, textures, sound and config, plus a standalone scripting evaluator and a Blender import addon

The original game
Bohemia Interactive's debut game, published by Codemasters as Operation Flashpoint in 2001, became a genre-defining combat military simulation and the No. 1 bestselling PC game around the world, winning many international awards, including "Game of the Year" and "Best Action Game". Over 2 million copies have been sold since its release.
Storyline
The horrors of WWIII are imminent.
There are clashes over the Malden Islands from dusk to dawn, and you are caught in between. You must use every resource in your arsenal to hold back the incoming darkness. Victor Troska came back to Nogovo, thinking the pain of war was buried in his past.
But his dream lies broken now.
His worst nightmare returns when military forces land near Nogovo.
Key Features
Cold War Assault
Command a squad of fully equipped troops

Over 40 authentic vehicles and aircraft

Immersive campaign and single missions

LAN/Internet multiplay

Vast 100km² battlezones

Resistance
Story-driven 20-mission campaign

Nogova, the new 100km² island

New vehicles, weapons and equipment

Detailed urban environments

Open source & modding
The full engine and game source code is available under GNU GPL v3.0-or-later: fork it, build it, port it, or contribute back. Game assets remain under the Arma Public License Share Alike (APL-SA). Mods can be browsed and installed directly through the in-game mod manager, and a free Demo lets you try the remastered engine before buying.
The full engine source code is available on GitHub - search for BohemiaInteractive/cwr