There's an excellent python-based downloader (https://pypi.org/project/humblebun...

There's an excellent python-based downloader (https://pypi.org/project/humblebundle-downloader/) that I linked to in the first Ars Technica comment.

The usage is very simple -- you login in a browser, find a cookie named _simpleauth_sess by the dev tools, copy it, and then paste it into single quotes (it includes double quotes!) in the below:

    hbd -s '"long_cookie_value_of_random_alpha_hash"' --library-path local_target_dir --progress

The net result is a long download, but it will get everything...