Had this done for a while now but forgot to post about it.
Download
- Source code, more info and usage examples: https://github.com/jacklul/e621-Pool-Downloader
- This script works out of the box after unpacking on Windows, on linux get php-cli and php-curl (optional, recommended).
Basically you launch it and give it either pool URL or just ID and it downloads it. It also saves pool ID in a hidden file in destination folder so in the future you can update the pool, good for ongoing comics. It will not delete any images that were removed from the pool while 'updating'.
Updated