Why isn't There a open-source (project) game?
excluding legacy game. There are many open-source games. There are few large-scale high-polish open source games because it's difficult to build a business model around that. Unlike non-game software, games are ~exclusively consumer-facing, so you can't sell support or use them as a loss leader, and they're standalone applications that are difficult to monetize with online features or to use as the core of a closed-source commercial product. That said, there are still lots of great projects out there (some of which have even had commercial success), for example: - https://github.com/a327ex/SNKRX - https://github.com/beyond-all-reason/Beyond-All-Reason also: https://triplea-game.org/ a strategy game set with many user-created scenarios osu! is probably the longest running financially successful game with a fully FOSS modern core (though a proprietary legacy core). And there are many other smaller projects that have seen plenty of success. There are also a lot of mods that run as FOSS projects on top of proprietary games. So yeah, there are some projects to look into Can you be a bit more specific/add a few more details? I think this is just stupid question, but I wonder in FOSS there is no game project that created from active community for alternative of another game. When we face a problem like paid software or problematic software that steal our data, the community will make the alterative for us but it is less possible for game generally. I wonder what your concept of "game" is. Maybe your question excludes offline and 2D games. (Lots of roguelikes.) In regard of "alternative to an existing game", there's 0AD, which resembles the Age of Empires series. https://en.wikipedia.org/wiki/0_A.D._(video_game)