Download the file unzip it and head into the folder. Since it use you can use dir /r command.
I noticed that some of the hidden files have unique number from the beginning. I use the sort command to find those unique files.
From here I open up each file manually to find hidden clues. Some files contains rabbit holes which are base64 encoded and you will eventually reach find the flag.
A nifty badge will be awarded once the challenge is complete.