The top 100 list has already been posted, but I thought this article makes some interesting observations on the list.
Overall the variety of games and experiences on that list really show how versatile the deck is, and that people can still have a great time with games that aren’t a perfect experience on the deck.
Yes, it requires it runs well with default settings, everything is accessible with the standard deck controls, that all the control displays use the steam deck icons, and it doesn’t reference controls the deck doesn’t have. It’s a very high bar.
Also UI has to look good at either 720p or 1280x800. A lot of modern games don’t do that well at low res.
And if there is a need to write text, it has to pop up the in screen keyboard automatically. Which afaik means “you have to implement the Steam Input API”, unless there is some hacky workaround for that. But in any case, it’s something the dev has to do specifically for Deck support, it doesn’t just happen.
Icons actually can just happen, as quite a few games use libraries that already have the SD icons included if it detects the controller type.
Steam did try to hack Wine’s handling of windows textboxes to automatically trigger the OSK. I’m not sure if they gave up there (or I got lucky in disabling it), but it suuucked. It’s very easy to get into fights with that auto-popup, particularly if you’re trying to do wine-tweaking tasks.
Elder scrolls online works perfectly , you just have to tap touchscreen to play on the launcher then close the launcher.