It's already one of Slay the Spire patch 2.3 has added full Steam Input so it can conquer the Steam Deck too. Additionally, one of its most popular mods has gone standalone, and developer Mega Crit reveals it is working on multiple "secret projects".
A fusion between card battler and Steam Deck compatible – although only 'playable' as it's noted that there are some control issues.
With the game's latest update, Mega Crit has added full for Steam Input, allowing s to play with "a wider variety of controllers and customise input settings through Steam's Controller Configuration". As the Steam Deck uses Steam Input, the developer notes that "Slay the Spire will work nicely out of the box". Alternatively, if you want to keep your current controller setup you can easily disable Steam Input instead.
Beyond that, popular fan expansion mod Downfall has been given its own Steam store page so s can access it more readily. This mod adds a new hero character called The Hermit, an alternative campaign, and allows players to control bosses such as the Slime Boss and the Guardian. You can even fight the potions lady if you wish.
Regarding Mega Crit itself, the update also teases that it's been hiring new people and has "begun developing secret projects", although the team adds, "do not ask us what these projects are. They are secret so we cannot tell you".
As for the Steam Deck, check out our review to find out why our reviewer called it "a buggy but brilliant handheld gaming PC".