Valve has their DRM solution ([1], "CEG"), but the DRM is fully optional, as it needs to be applied by the game developer to their executable before they upload their game.
I don't have good examples in mind right now, and I would need to double check, but I am pretty sure I was able to launch Supreme Commander 2 trough wine directly with the game executable, without launching Steam some time ago. I also recall "Tyranny" doing a free week-end, after which I could still launch the game trough the executable (although steam refused to launch it). That was a Linux game, though, and could be slightly different.
I would roughly estimate that more than 20% of my Steam library does not have DRM attached to it. There are a couple lists out there that help find DRM-free games on Steam [2][3][4], etc.
Some game developers advertise this as a feature of their game on Steam. For others, it could be an oversight. I find it pretty convenient in any case (example: copy FTL on a USB stick for playing on the go, even without internet connection on an underpowered computer). It also helps with wine.
I don't have good examples in mind right now, and I would need to double check, but I am pretty sure I was able to launch Supreme Commander 2 trough wine directly with the game executable, without launching Steam some time ago. I also recall "Tyranny" doing a free week-end, after which I could still launch the game trough the executable (although steam refused to launch it). That was a Linux game, though, and could be slightly different.
I would roughly estimate that more than 20% of my Steam library does not have DRM attached to it. There are a couple lists out there that help find DRM-free games on Steam [2][3][4], etc.
Some game developers advertise this as a feature of their game on Steam. For others, it could be an oversight. I find it pretty convenient in any case (example: copy FTL on a USB stick for playing on the go, even without internet connection on an underpowered computer). It also helps with wine.
[1]: https://partner.steamgames.com/doc/features/drm
[2]: https://steam.fandom.com/wiki/List_of_DRM-free_games
[3]: https://pcgamingwiki.com/wiki/The_Big_List_of_DRM-Free_Games...
[4]: https://store.steampowered.com/curator/7540156-DRM-Free-Game...