The promise of Valve’s new Steam Deck is to let you play in your Steam catalog anywhere. But thanks to the particular composition of the operating system of the new handheld PC, there may be some important warnings to this promise.
As a Linux-based system, Deck's SteamOS has a somewhat limited selection of compatible games. To combat this, Valve developed a feature called Proton, which uses a fork of the Wine compatibility layer, which is designed to help run native Windows titles on the operating system, and while this expands the list of compatible games SteamOS, there are some notable exceptions.
According to ProtonDB, almost half of the 10 most popular games on Steam – Destiny 2, Apex Legends, PUBG and Rainbow Six Siege – will not work on SteamOS. It seems that the culprit is anti-cheating software. In most cases, games will start, but their anti-cheating systems will not, so you will not be able to log in to multiplayer servers.
Valve yes you notice that Steam Deck will come with a new version of SteamOS and that it is currently "improving game compatibility and support for Proton's anti-cheating solutions by working directly with vendors." In short, developers will not to own go through hoops for your games to work on SteamOS, but it would help if their anti-cheating vendors did.
We contacted Valve for feedback on exactly how it works to improve SteamOS compatibility.
This is really the crux of the matter. Despite Switch comparisons, the Steam Deck is still a PC. And, as a direct computer, Valve is also pleased to let you play with the machine at will, that is, you install Windows freely.
Unfortunately, PC games have always meant that sometimes games don't work as expected. This is no less true for Steam Deck than for any desktop tower you've ever owned.