Mac, and Mac only. macOS 14 (Sonoma) at minimum, on Apple silicon as well as Intel.
There is no Windows version, no Linux version, no iPhone or iPad version, and none is planned: the app rests entirely on the macOS wallpaper mechanism, which has no equivalent anywhere else.
This is the normal behaviour on first launch for an app distributed outside the Mac App Store, signed and notarised by Apple included.
Go to System Settings → Privacy & Security, scroll to the message naming MyDynScreen, and click "Open Anyway". Once, and never asked again.
Every one the system reports. The picture is cut at each display's real bounds, including when your panels differ in resolution, orientation and pixel density.
Setup actually tested so far: to be filled in.
Decoding is hardware-accelerated and shared across displays — one pass, not one per panel. The wallpaper suspends when you leave a desktop, and it can suspend on battery.
Only the ones you explicitly ask for, and never without a backup first. Each original value is recorded at the moment it is taken, and handed back exactly as it was when you take control again.
Drag the app to the Trash. Before that, use the Maintenance screen to restore your wallpapers to their original state: that is what hands back cleanly what the app had taken.
No. No telemetry, no account, no identifier. The only network call is the update check, and it can be switched off.
The store's sandbox forbids writing the system's animated wallpaper files, and the interface that lets an app be a wallpaper provider is not public. No app in this category is on the store, for the same reason.