Project is seemingly dead with the latest commit being from 2018.

Two major games with code on github I can think of are Amnesia: The Dark Descent (1) and Celeste (2)

(1) https://github.com/FrictionalGames/AmnesiaTheDarkDescent (2) https://github.com/NoelFB/Celeste

Also mindustry (1) which is a factorio-like game with tower defense elements. Great game and still in active development.

(1) https://mindustrygame.github.io

Mindustry is such a great game. I bought it for like $4 when it was on sale on steam, and played it for >200hrs.

Can definitely recommend, it beeing open source is really just the cherry on top.

Also missing Cortex Command[0] which got open sourced not so long ago[1].

[0]: https://store.steampowered.com/app/209670/Cortex_Command/ [1]: https://github.com/DataRealms/CCOSS

there's also https://github.com/TerryCavanagh/VVVVVV

which spawned quite a lot of discussion here. https://news.ycombinator.com/item?id=22011358

Celeste is really great! But the github repo only contains some class files from the game, 'for inspiration'. So it is just a small sample. Also there is no artwork. I would not call that 'a game hosted on GitHub'

I'm always surprised by lists like these that fail to mention Space Station 13, the most actively developed 10+ year old FOSS game on GitHub. There are numerous forks of it, with tgstation being the most popular one [1].

SS13 is multiplayer round-based role playing game, where players assume the role of a crewmember on a space station. Together they must keep the station running smoothly, whilst dealing with antagonistic forces who threaten to sabotage the mission.

Since most stations have dozens of job roles, each with content enough to last you hundreds of hours it's no surprise why people such as myself have spent thousands of hours on it and thousands play this every day. It has systems as varied as atmospherics, fully destructible environments, surgery, genetics, science, engineering, etc etc and the amount of content and interaction possible means that no two rounds are the same. Here's a very popular review which shares stories of some of the crazy events that can happen [2].

Unfortunately it's all built on the proprietary engine BYOND. However there are fully libre successors on new FOSS engines which are in-progress to match the massive amount of content SS13 has already accumulated, such as SS14 [3] and Unitystation [4]. I'm not a hardcore FOSS enthusiast about games so I prefer the amount of content SS13 has for the time being, but in time I intend to play and contribute to one of the successors instead in the future. They both have active servers if you're interested in playing them right now, with SS14 also already being available on Steam.

Watch the review at least, you won't regret hearing the funny stories at the very least.

[1] https://github.com/tgstation/tgstation [2] https://www.youtube.com/watch?v=URJ_qSXruW0 [3] https://spacestation14.io [4] https://unitystation.org

I've played Endless Sky and liked it a lot; although I'm pretty bad at combat.

Some other games: https://store.steampowered.com/curator/38475471-Libre-Open-S... https://github.com/Martin-Pitt/awesome-frontend-games (<- I haven't checked if these are FLOSS, but I had this in my bookmarks)

There are also many mods for games available in GitHub such as: https://github.com/cybrxkhan/VIET-Events-for-CK3 https://github.com/kiooeht/ModTheSpire

Tales of Maj'Eyal is an excellent rougelike. https://te4.org/ Though the source is on a gitlab server https://git.net-core.org/groups/tome

I also want to highlight mindustry as mentioned elsewhere.

Assault Cube seems to have gotten their source code on github! https://github.com/assaultcube/AC There are still some people (sometimes me) playing on the multiplayer server.