Making a Godot game ready for Steam Deck

Everything that makes a Godot game Deck-ready follows from that sentence: it runs Linux, so export for Linux or rely on Proton; it has a gamepad, so the game must not need a mouse; and its screen is 1280 by 800 at handheld distance, so text sized for a 1080p monitor is too small.

• Native Linux: add a Linux export preset (x86_64) and upload it as its own depot. No Proton layer, fewer surprises.
• Windows through Proton: works for most Godot games; test it, since Valve rates games Unsupported if Proton blocks them.
• GodotSteam ships Linux libraries too, if you use it.

• Input: map every action to joypad events in the Input Map; make menus focusable (focus_neighbor, grab_focus on open) so the gamepad can reach everything.
• Glyphs: show gamepad button icons when the last input was a gamepad; never show keyboard keys to a Deck player.
• Text entry: open Steam's on-screen keyboard (GodotSteam exposes it) or offer a gamepad-friendly entry.
• Readability: set Display > Window > Stretch Mode to canvas_items, design for 16:10, and keep the smallest text at least 9 pixels tall at 1280x800.
• Performance: 30 fps at 800p in the default settings. Godot's Forward+ renderer runs on the Deck's Vulkan driver; if you are close, make the defaults lighter (shadows, resolution scale).

Run the game at 1280x800 windowed on your PC with a controller only, from launch to the end of a session, before you ever touch a Deck. Then test on a Deck if you can, and request Valve's compatibility review from the app's landing page once the build has passed its standard review.

Flockbay builds games on the official Godot engine; the project is an ordinary Godot 4 project, so Godot's own export makes the Linux build. Flockbay's playtests report frame times and hardware from testers' machines. Building is free.