Lutris is an Open Source gaming platform for Linux. It installs and launches games so you can start playing without the hassle of setting up your games.
Get your games from GOG, Steam, Battle.net, Origin, Uplay and many other sources running on any Linux powered gaming machine.

In Linux, typically, when there's a solution to a problem, there are seven other solutions to the same problem. But not so when it comes to Linux gaming. Here, we only have several incomplete solutions to a rather big problem. Steam did massively improve the situation, and it looks like the most mature and likely technology slash software to bring parity to the Linux gaming scene. Still, it's not a perfect fix.

There are many Linux games that don't quite fit the Steam category [sic]. You have old games, indie games with their distribution channels, Windows games that need WINE, and so forth. If you want to have all these under a single umbrella, there isn't really a solution. Well. Maybe. A challenger appears: Lutris. Let's have a review.
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As I continued exploring Lutris, I got to appreciate its versatility more and more. Sure, more of the good stuff is hidden behind an unnecessary layer of classic Linux nerdiness, which will be the biggest obstacle to ordinary folks, but it did work and behave rather well. Lutris supports numerous runners, which you can install and configure separate from any game. Or if you install a game that requires it, it will be set up at that time. As I mentioned earlier, the various runners let you sample DOS, Amiga, Atari, GOG, Steam, and more.
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There were a few small annoyances. Once, Lutris crashed, for seemingly no good reason. When installing things, you may end up supposedly starting two instances of Steam, which you can't really do. Not a biggie, just something to remember. Lastly, you can do a lot of manual tweaks and overrides, and also filter your games based on type, like pure native Linux, Steam, WINE, etc.
Conclusion
Among the many different Linux gaming platforms, aggregators, launchers, and frontends, Lutris is the one that has given me the highest success rates so far, by a nice margin. I was most pleasantly surprised that it can support both the Linux and Windows versions of Steam side by side, and that you don't need too much technical expertise to install games. The runners do all the black magic for you. Very cool.