From Space Empires to Spellbooks: Ten More Open Source Games

Continuing our 30th anniversary tour of free and open source Linux games, this second batch of ten spans genres from 4X strategy to fast-paced arena shooters. Each project is community-driven, openly developed, and ready to download today.

Master the Galaxy with FreeOrion

FreeOrion is a turn-based 4X strategy game—eXplore, eXpand, eXploit, eXterminate—set in a randomly generated galaxy. Inspired by the Master of Orion series, it is neither a clone nor a remake. Players colonize planets, research technologies, and contend with a variety of formidable species.

The project’s FOCS (FreeOrion Content Script) files let the community customize mechanics, presentation, and nearly every other aspect of the universe. A simple example defines a small Krill space monster:

MonsterFleet
    name = "SM_KRILL_1"
    ships = [
        "SM_KRILL_1"
    ]
    spawnrate = 0.5
    spawnlimit = 9999
    location = And [
        Not Contains Monster
        Not WithinStarlaneJumps jumps = 2 condition = Contains And [
            Planet
            OwnedBy affiliation = AnyEmpire
        ]
    ]

Contributions of all kinds are welcome, from programming and design to bug reporting, playtesting, and translation. The project wiki lists specific areas where help is needed.

Classic Roguelike Challenge: NetHack

NetHack descends directly from the 1982 game Hack. Choose a character class and fight through procedurally generated dungeons in search of the Amulet of Vendor. The learning curve is steep but rewarding.

Because the code is open, curious players can read exactly how the game works. For example, a well-placed comment in the source explains the quirky behavior of a thrown boomerang:

register int i, ct;
int boom; /* showsym[] index  */
struct monst *mtmp;
boolean counterclockwise = TRUE; /* right-handed throw */

/* counterclockwise traversal patterns:
  *  ..........................54.................................
  *  ..................43.....6..3....765.........................
  *  ..........32.....5..2...7...2...8...4....87..................
  *  .........4..1....6..1...8..1....9...3...9..6.....98..........
  *  [email protected][email protected][email protected]@......@[email protected][email protected].....@9..
  *  .3...9....6..9....89.....................1..4...1..6....1..8.
  *  .4...8.....78.............................23....2..5...2...7.
  *  ..567............................................34....3..6..
  *  ........................................................45...
  * (invert rows for corresponding clockwise patterns)
  */

bhitpos.x = u.ux;
bhitpos.y = u.uy;
boom = counterclockwise ? S_boomleft : S_boomright;

The game’s competitive scene is active enough that GitHub HQ once hosted the annual Roguelike Celebration, featuring a live speedrun by Mikko Joula (aka Adeon), the record holder for fastest real-time ascension.

Arcade Racing: Stunt Rally and Pixel Wheels

Stunt Rally may not have seen an official release in five years, but the creator @cryham put five solid years into it and it still holds up. More than 20 cars and 172 tracks span multiple terrains and planets, with network and splitscreen multiplayer plus a built-in track editor.

On the smaller scale, Pixel Wheels is a top-down racer from @gateau that runs on Linux and Android. Still in progress, it offers a variety of tracks, vehicles, and punchy power-ups. Its release notes also demonstrate how to publish updates with GitHub Pages—the Markdown source for version 0.20.0 is notable as a clean example.

Fast-Paced FPS: Red Eclipse 2

Red Eclipse 2 is a first-person shooter built around parkour, dashing, and impulse boosts. Development has stretched past a decade, and the game includes an editor for creating maps cooperatively online in real time.

The engine underneath, Tesseract, is a fork of the Cube 2: Sauerbraten engine, written by developer @lsalzman.

Empire Building: Freeciv and Unknown Horizons

Freeciv is the turn-based civilization builder that supports up to 126 players (500 on the web version), with more than 500 nations and 50 playable units. Lead your empire from the stone age to the space age.

The game is maintained by an international team and localized into 36 languages, including Scots Gaelic.

On the real-time side, Unknown Horizons is an economy simulation inspired by the Anno series. Grow a small settlement into a healthy colony by collecting taxes and keeping inhabitants happy. The current build runs on FIFE (“Flexible Isometric Free Engine”), a C++ isometric game engine, though the team is porting the project to the Godot engine.

Space Trading and Combat: Endless Sky and Vega Strike

Endless Sky lets you pursue any career in space: trader, pirate, or mercenary. Earn enough to pay off your starter ship’s loan, then buy new vessels and upgrade weapons and engines. The project actively seeks storytellers and content creators—non-programmers can contribute missions, ships, weapons, aliens, audio, and visual assets.

Vega Strike is a 3D space flight simulator in the vein of Freelancer, but free. Explore, trade, and fight from the cockpit. Coders, artists, writers, and testers can find guidance in the repository’s CONTRIBUTING.rst.

Modern Roguelike: Dungeon Crawl Stone Soup

Dungeon Crawl Stone Soup (DCSS) is a roguelike that can be downloaded, built from source, or played over telnet/SSH. The website even offers a live view of players around the world exploring dungeons. The latest release, 0.27 “The Cursed Flame,” adds new spells, spell books, and maps.

A memorable bug in the project’s history: a single commit quietly doubled all melee damage dealt by players. The error went unnoticed for nearly two weeks, surfacing only when the game’s win rate spiked noticeably.