Valve's claim that the Steam Deck would run every game in your Steam library is looking more and more like fact. Yesterday Easy Anti-Cheat announced support for Linux and the Proton compatibility laters the Deck relies upon.
Today, BattlEye Anti-Cheat followed suit, announcing they'd support the Steam Deck and Proton in a tweet.
"BattlEye has provided native Linux and Mac support for a long time and we can announce that we will also support the upcoming Steam Deck (Proton)," reads the tweet. "This will be done on an opt-in basis with game developers choosing whether they want to allow it or not."
BattlEye has provided native Linux and Mac support for a long time and we can announce that we will also support the upcoming Steam Deck (Proton). This will be done on an opt-in basis with game developers choosing whether they want to allow it or not.— BattlEye (@TheBattlEye) September 24, 2021
Steam Deck will run a new version of SteamOS, relying on the third-party software Proton to make Windows games compatible with the Linux-based operating system. The issue with Proton is that it previously wasn't supported by certain pieces of anti-cheat software. That meant it was looking like games such as Apex Legends wouldn't work on Valve's handheld.
That's changed quite suddenly in the past couple of days. Easy Anti-Cheat's support for Proton means Apex Legends ought to work on the Steam Deck. The BattlEye announcement isn't as large a shift given its existing support for Linux, but confirmed support for Proton and the Steam Deck will mean Fortnite, PUBG, Rainbow Six Siege, Ark: Survival Evolved and many more ought to work, too.
Earlier this month, the president of CodeWeavers, co-developers of Proton, caused a fuss when they said that the Steam Deck wouldn't really run every game on Steam at launch, arguing that Valve only meant the hardware was capable of it. He also said that Proton was a "living, breathing project" however, and that more games would be supported in the future.