name 'ImpromptuNinjas' could not be found

[prismspecs]

Assets\ExecutableServices.cs(3,7): error CS0246: The type or namespace name 'ImpromptuNinjas' could not be found (are you missing a using directive or an assembly reference?)

I get the above error when I try to run the Unity demo on Windows

[Armitage1982]

This is because NuGetForUnity is only compiled after the demo files and therefore the dependencies cannot be downloaded.
Just remove temporarily the files and folders that cause errors, let the NuGetForUnity do its job, then restore those files.
You will probably need to reload your Unity project after that to preload everything correctly.