I was just working on this: wget -r -A.pdf http://twvideo01.ubm-us.net/o1/vault/GD_Mag_Archives/

but getting a 403 (forbidden). Now I see I should have tried http://gdcvault.com/gdmag instead of copying the link from right clicking and saying "Save As"

You do have a few more flags than I do. I should look those up.

Edit: Thanks for expanding your post to explain all the flags. Very helpful.