There are some open source games but they tend to be more like engines than proper games, or are very niche. Some rather popular example:
- Nethack: Maybe the most "complete" open source game I can think of, if you like ASCII characters for graphics.
- Freeciv: The engine is original, but the game logic and assets are a complete ripoff.
- Stepmania: a DDR clone, useless without user contributed (and often illegal) songs.
- SCUMMVM: that's an engine, not a game
There are also plenty of smaller games, some of them of playable but they tend to be at "school project" level. Well below the standards for popular indie games.
As for OpenDiablo2, it is yet another engine, not a game.
I think the open source model can make good engines, because everyone can pick it up and contribute the few features they want, allowing for gradual improvement that the original developers can benefit from.
But for a complete game, you usually need a more global approach, and a lot of work making assets, open sourcing will probably benefits your competitors more than you: once your game is complete, there is little need for you to take advantage of the work of others.
Wing Commander (not sure about the name, played it a long time ago)
Endgame: Singularity
All of those are really good free software games that I played myself. There are a lot more, but I have not played them so I don’t really know how good or bad they are.
There are some open source games but they tend to be more like engines than proper games, or are very niche. Some rather popular example:
- Nethack: Maybe the most "complete" open source game I can think of, if you like ASCII characters for graphics.
- Freeciv: The engine is original, but the game logic and assets are a complete ripoff.
- Stepmania: a DDR clone, useless without user contributed (and often illegal) songs.
- SCUMMVM: that's an engine, not a game
There are also plenty of smaller games, some of them of playable but they tend to be at "school project" level. Well below the standards for popular indie games.
As for OpenDiablo2, it is yet another engine, not a game.
I think the open source model can make good engines, because everyone can pick it up and contribute the few features they want, allowing for gradual improvement that the original developers can benefit from.
But for a complete game, you usually need a more global approach, and a lot of work making assets, open sourcing will probably benefits your competitors more than you: once your game is complete, there is little need for you to take advantage of the work of others.