Here is the full list of all 7 Wallpaper Alive achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Subscribe and install 3 or more workshop items
Upload a wallpaper to the steam workshop
Set your wallpaper to an item from the workshop
Click the donate button (No donation required)
Modify your desktop
Set your desktop to a Gif
Launch Wallpaper Alive