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'