Field manual

Linux & Steam Deck status DECK: UNSUPPORTED

On a Linux desktop it just runs: ProtonDB rates it Gold, and EAC authenticates into multiplayer normally. On the Steam Deck itself Valve has now officially rated it Unsupported — that is a performance ruling, not an anti-cheat block: you cannot turn the graphics down far enough for the handheld. Both verdicts are true at the same time, and this page keeps them apart.

New on Aug 20: Valve's Deck Verified badge is no longer "Unknown". The Steam store page now shows Steam Deck Compatibility: Unsupported, with Valve's stated reason quoted exactly as it appears: "This game's graphics settings cannot be configured to run well on Steam Deck." Read that precisely — it is a performance ruling, not an anti-cheat or compatibility block. Nothing about EAC, Proton or launching the game changed; Valve is telling you the settings floor is still above what the Deck can hold. Verified this round directly on Valve's own store page and mirrored on ProtonDB.

What we actually know

Deck hands-on, launch day: Steam Deck HQ booted the shipped build, got through the tutorial and a full live match with no EAC block. Performance: even on lowest settings with TSR at 35%, framerate dropped below 30 while walking and hovered around 30 FPS overall — their verdict is "not a game to play on the deck" handheld-first, though they expect it to fare better on Steam Machine at 1080p or lower.
Independent corroboration: ProtonDB rates the game Gold (35 reports as of Aug 20, up from 19 at launch) — multiple separate Linux/Proton users report it installs and launches "fine out of the box, no tinkering," with EAC authenticating into multiplayer normally on the live build. The most recent report at the time of writing is a plain "Game ran instantly, no issues so far" on Proton 10.0-3. Note the split: Gold is a desktop-Linux verdict, and it does not contradict Valve's Unsupported rating for the handheld — the first says Proton runs it, the second says the Deck can't push enough frames.
The two Deck-specific reports say the same thing the badge does. Filtering ProtonDB to Steam Deck hardware leaves just two reports, and only one is from the shipped build: a player six days ago summed it up as "linux maybe, steam deck no" — flagging Significant Performance Problems, heavy and minor graphical artifacts plus missing textures, text too small to read ("the tips ted to be small. same for the server browser"), and a hard number: "on low graphics with upscaling to high i was getting 25 maximum FPS." That is one person's measurement on one Deck, not a benchmark average — but it lands in the same place as Steam Deck HQ's independent hands-on and as Valve's ruling, which is why we're comfortable leading with it.
The anti-cheat is kernel-level Easy Anti-Cheat, and the developer did carry the Proton-enabled switch from beta into launch — the open question from Aug 8 (whether launch EAC config would match the beta) is now resolved: yes, it matches.
Performance complaints aren't Deck-exclusive. Separate Steam Discussion reports describe sub-60 FPS stutter on desktop Windows/Linux hardware too (e.g. an RX 9070 XT system reporting 29–42 FPS) — so the Deck's low framerate is likely general launch-day optimization, not a handheld-specific penalty.

If you're buying primarily for Deck: three independent lines of evidence now point the same way — Valve's Unsupported ruling, Steam Deck HQ's launch-day hands-on (~30 FPS, dipping below while walking, at lowest settings with TSR 35%), and the one shipped-build Deck report on ProtonDB (25 FPS max on low + upscaling). Treat it as a "docked to a TV" or Steam Machine game rather than a handheld one. Steam refunds cover <2h played within 14 days if that's a dealbreaker.

Known Linux issue: Epic account linking fails

One recurring Linux-specific problem shows up across multiple independent ProtonDB reports (from the beta through the live build): the game itself runs fine, but linking your Epic account for cross-platform progression fails — the EOS overlay reports "Title was not launched correctly" or the Epic sign-in silently loops. At least three separate reporters describe the same symptom; it does not affect joining servers, only Epic/EOS sign-in.

One reporter (via ProtonDB, on the live build) traced it to EOS bootstrapper environment variables being lost through the EAC spawn chain under Proton, and posted launch-option env vars (EOS_SESSION_STARTUPINFO/EOS_SESSION_GUID) that fixed sign-in for them on two Proton versions. That's a single unconfirmed workaround, not a Team17-confirmed fix — if you try it, you're beta-testing someone else's theory. If Epic linking isn't critical for you, skipping the Epic login entirely is the low-effort route (one reporter: "with skipping Epic login, works perfectly").

Still open

No developer statement confirming Deck support was an intentional launch target (it works, but appears untuned for it). Valve's Unsupported rating is a Valve judgement, not a Team17 position — Team17 has said nothing about the Deck either way.
Microphone not captured on Linux. A shipped-build ProtonDB report (five days ago, Nobara Linux 42, NVIDIA 570.144, ~3 hours played) puts it precisely: "Although detecting my microphone, audio not captured." The reporter tried both GE-Proton latest and Proton Experimental with PROTON_ENABLE_WAYLAND=1 and says the problem persisted through all of them. Still a single report — but it's a detailed one on the live build, and it rhymes with the VOIP problems the game has on every platform (voice chat page). If you rely on the mic, treat Linux as unverified for VOIP.
Whether Valve revisits the Unsupported rating after Patch 1.2 — that patch promises broad stability and optimisation work, but Team17 has named no Deck-specific or graphics-floor changes (what's confirmed in Patch 1.2).

Playing on a Deck means no room for a second window. Our mortar & artillery calculator is built mobile-first and works offline once loaded — keep it open on your phone and read grid, range and elevation off that instead.

Last verified Aug 21, 2026 ~02:00 UTC — this round re-read ProtonDB at source: still Gold, still 35 reports, Deck Verified Status still Unsupported with Valve's stated reason unchanged, and still only 2 Steam Deck reports. The page title and opening answer were rewritten this round so the Linux verdict leads and the Deck verdict follows — no factual claim changed. Everything below was verified on Aug 20 and is unchanged: Valve's badge move from "Unknown" to Unsupported read off the Steam store page, the one shipped-build Deck-hardware report (25 FPS max, artifacts, unreadable text), the Linux microphone-capture detail, the Epic/EOS account-linking section (3+ independent reports, workaround still single-source), and the core "it launches and EAC works" verdict from the Aug 13 Steam Deck HQ hands-on.