This is my first time doing this, so hopefully it's the correct way to do so.
The information on this page seems to be outdated as since the full release of Little Witch Nobeta, the game will attempt to open Steam upon being launched and if Steam isn't allowed to be ran, the game will stay on a black screen indefinitely.
I am unsure what method of DRM is being used in this scenario, but the game is fully unplayable without Steam from my testing with all versions post early access.