When installing via pip the pdf-link-checker is copied to Python's scripts folder (registered as PATH).
Calling the script with pdf-link-checker my-awesome-slides.pdf as described in README doesn't work as windows doesn't associate the file as python script due to missing file extension.
possible workaround:
call via py %USERPROFILE%\AppData\Local\Programs\Python\Python39\Scripts\pdf-link-checker my-awesome-slides.pdf
suggestion for solution:
update file to include file ending *.py when installing under windows. This would enable being called form CMD with pdf-link-checker.py my-awesome-slides.pdf