Ahead of Steam Deck's launch in December, Valve is reviewing "the entire Steam catalog" to check each game's compatibility with the handheld. That presumably means everything, from stuff like Poop Plague in Fairyland through to Cyberpunk 2077. Each game will be categorised based on its compatibility, ranging 'Verified', 'Playable', 'Unsupported' and 'Unknown'. Icons for each category will display on the game's listing.
Those categories are pretty self-explanatory:
- Verified means that the game has full controller support, no compatibility warnings, support for the Deck's native resolutions and complete system support ranging its middleware through to any anti-cheat software.
- Playable means some tweaking may be necessary, with Valve's example being a game that may require a "user to manually select a community controller config, needing to use the touchscreen to navigate a launcher, etc."
- Unsupported means the game doesn't work (Valve uses Half-Life: Alyx as an obvious example)
- Unknown means Valve doesn't know, compatibility has yet to be checked.
Navigating to a game's store page will provide a more thorough breakdown of why a game may be deemed just 'Playable' rather than 'Verified', or why it won't work. For Team Fortress 2, for example, the store warns that it has "missing or inaccurate controller glyphs" and that you'll need to use the virtual keyboard for some features. If you can cope with those things, you can still play the game.
The Steam Store on Deck will prioritise Verified games by defaulting to a "Great on Deck" tab. To search the whole store, you'll just need to navigate to the full store home tab.
Valve's review process is ongoing, and it'll keep going post-launch. It seems like a truly gargantuan operation given how massive Steam's library is, and given that Valve has promised to re-review games after updates. Before launch, Valve intends to roll out a way to check your library's compatibility ahead of the handheld's availability.