Best Open Source Games: Only 7 Actually Deserve Your Time

Let me save you some time: there are not fifty great open source games. There are not even twenty.

Search this topic and you will drown in listicles recycling the same zombie projects — games that got abandoned in 2016, "classics" nobody has launched in a decade, and tech demos wearing a game's clothes. I went through that pile so you don't have to. What survived the cut is seven games. Seven. But every single one of them is the real deal: completely free, no ads screaming at you between levels, no energy timers, no "remove ads for $4.99" hostage negotiations. The source code is public, the communities are alive, and the games are just… good. Like, embarrassingly good for something nobody charges you for.

Here's the shelf.

1. Mindustry — The Factory That Fights Back

If I could only keep one game on this list, it's this one, and it's not close.

Mindustry is a factory-building game welded to a tower defense game, with RTS on top just to show off. You build conveyor belts and supply chains to feed ammunition into your turrets, produce materials, construct an army of mechs and ships, and defend your core against waves of enemies who are genuinely trying to find the weak spot in your base — not politely walking down a fixed path like in lesser tower defense games.

The campaign spans two planets, Serpulo and Erekir, with 35 hand-made maps and over 250 procedurally generated sectors. There are 250+ technology blocks to master and cross-platform multiplayer, co-op or PvP, so your beautiful factory can get destroyed by friends instead of strangers.

Players agree with me, by the way: it holds a 4.5 out of 5 on Google Play from around 129,000 reviews, and the most common word in those reviews is "masterpiece" — usually followed by disbelief that it's free and ad-free. It is. Play it on Android or PC.

Play/download: https://play.google.com/store/apps/details?id=io.anuke.mindustry

2. Shattered Pixel Dungeon — The Roguelike That Owns Mobile

Most mobile RPGs are slot machines in a wizard hat. Shattered Pixel Dungeon is the opposite: a proper, old-school roguelike dungeon crawler that's simple to start and absolutely brutal to master.

Every run is different — randomized layouts, enemies and loot across 5 dungeon regions and 26 floors. You get a choice of heroes, each with subclasses, talents and endgame abilities, over 250 items to find and craft through alchemy, 60+ enemy types, traps everywhere, and bosses that will end your confident little run without blinking. You will die. A lot. And you will immediately start again, because the game is fair in a way most roguelikes aren't: it gives you information, and what you do with it is on you.

It's been in active development for over a decade, updates land every few months, and players rate it 4.8 out of 5 on Google Play from more than 160,000 ratings — one of the highest-rated games on this entire site, full stop. Android, iOS and PC.

Play/download: https://play.google.com/store/apps/details?id=com.shatteredpixel.shatteredpixeldungeon

3. Unciv — Civilization Without the Price Tag (or the Ads)

"Just one more turn" has destroyed more sleep schedules than coffee ever will, and Unciv delivers the full disease for free.

It's an open-source reimplementation of the classic civilization-building formula: found cities, research technologies, expand, trade, scheme, and eventually explain to your friends why your peace-loving empire absolutely had to build those warships. It's fast, it's tiny (the whole thing is smaller than most games' day-one patches), and it runs on phones that would cry trying to open a modern strategy game.

On Google Play it sits at 4.6 out of 5 from roughly 51,000 reviews, and scrolling those reviews is just page after page of people saying the same thing I am: no ads, no microtransactions, no nonsense — just the game. Android and PC.

Play/download: https://play.google.com/store/apps/details?id=com.unciv.app

4. The Battle for Wesnoth — 20 Years Old and Still Winning

Turn-based strategy fans talk about Wesnoth the way chefs talk about that one knife they've owned forever. It launched in the early 2000s and never stopped being developed, translated, modded and loved.

It's a high-fantasy tactical strategy game: move units on a hex grid, manage gold and villages, keep your veteran units alive because losing a leveled-up knight you've carried through six scenarios hurts like real grief. There are full single-player campaigns, online and hotseat multiplayer, and a mountain of community-made campaigns and mods built over two decades.

How alive is it? It's still one of the most-downloaded open source games in the world, pulling thousands of downloads every single week. Games don't survive 20 years on nostalgia. They survive on being excellent. PC, Android and iOS.

Play/download: https://www.wesnoth.org

5. OpenTTD — The Transport Empire That Never Closed

In 1995, Transport Tycoon Deluxe taught a generation that trains are cooler than sports cars. OpenTTD is the open-source remake and expansion of it, and somehow it's still the best transport tycoon you can play.

You build transport networks — road, rail, water and air — connecting industries and growing cities across enormous procedurally generated maps, up to 4096 by 4096 tiles. Hundreds of vehicles, full production chains, and multiplayer for up to 256 people, because apparently someone once looked at a train simulator and thought "needs more chaos."

It holds a 4.2 out of 5 on Google Play from around 40,000 ratings, with about 2.5 million installs on Android alone, and the PC version has been a permanent resident on strategy fans' hard drives for years. Fair warning: you will sit down for twenty minutes and stand up three hours later with strong opinions about railway signalling. PC, Android and more.

Play/download: https://www.openttd.org

6. 0 A.D. — Age of Empires Energy, Zero Price

This is the ambitious one. 0 A.D. is a free, open-source historical RTS built by Wildfire Games, a global team of volunteers, covering warfare and economics between 500 BC and 1 BC. Athens, Rome, Carthage, Sparta, Persia and more, each with their own units, buildings and strengths, all researched with frankly unreasonable attention to historical detail — units are named in their original languages, because of course they are.

You gather resources, build your city through village, town and city phases, raise an army, research tech and fight land and naval battles, solo or in peer-to-peer multiplayer. It began life as an Age of Empires II mod concept back in 2001, the team decided a mod was too small for what they wanted, and they just… built the whole game instead. And gave it away.

It's still in active development — this is a living project, not a finished museum piece — and everything is open: the engine code under the GPL, the art and music under Creative Commons. Windows, macOS and Linux.

Play/download: https://play0ad.com

7. SuperTuxKart — Mario Kart's Open-Source Cousin

Every list needs one game you can hand to literally anyone, and this is it. SuperTuxKart is a 3D kart racer built on one design rule: fun over realism. Karts, nitro, bananas, bowling balls, plungers — if it can be thrown at a rival, it's probably in here.

There's a story mode, Grand Prix cups, time trials, battle mode, soccer mode (yes, really), online racing, and a pile of community add-on tracks and characters. It holds a 4.3 out of 5 on Google Play from thousands of ratings, with over a million Android downloads, and it runs on hardware that modern racing games wouldn't even wake up for.

Is it Mario Kart? No. Does it cost anything, show ads, or ask your kids for in-app purchases? Also no — and on a family tablet, that second set of answers matters more than the first. PC, Android and more.

Play/download: https://supertuxkart.net

So, Which One First?

Short on time? Shattered Pixel Dungeon — five minutes to learn, months to beat. Want depth? Mindustry, and I'll see you in a month. Want the "one more turn" life? Unciv. Playing with kids or friends? SuperTuxKart. Nostalgic for the golden age of PC strategy? OpenTTD, Wesnoth and 0 A.D. are waiting, and they never left.

That's the real lesson of open source gaming: the great ones aren't great despite being free and community-built. They're great because of it — nobody's quarterly earnings call ever forced a battle pass into Wesnoth. Seven games, zero ads, zero catch. That's a better hit rate than most paid stores manage.

This list is alive — if a new open source game ever earns a seat next to these seven, it goes in. Most won't. That's the point.