The Steam Deck has been on the market since April and, in that time, Valve has been ranking games based on their playability on the device.
Why Verified? Why Playable?
The Deck is built from the ground up as a Linux device, running SteamOS 3.3 as of the time of writing this. But many games are designed to run with Windows and not Linux. Valve has developed a solution, though, called "Proton." It's a compatibility layer between the Linux operating system and the Windows environment that games expect.
So one of the primary dimensions of ranking here is based on their compatibilty with Proton.
Furthermore, many titles on Steam were built expecting the player to be sitting at a desktop computer with a 1080p monitor around 5 feet from the user. That's why games are also checked to see if in-game text appears readable on the Steam Deck's screen. There are other dimensions that are checked for compatibility, too. Read more here.
Valve's building a catalog of games that work well on their new handheld. They've set forth a criteria from which new games will be judged. And they're curating a new class PC game that can be comfortably played on a handheld.
So if we look at SteamDB, we can see that there are now 4,503 titles ranked as either "Verified" or "Playable" on Steam Deck. That's a pretty solid achievement.
There are many titles on this list including:
This is a pretty impressive feat for Valve's team. Keep in mind that Valve is a relatively small company. For them to be able to rank so many games based on such stringent criteria is impressive.