The "Plus-Size AT-AT" has the same playability and basic structure of LEGO's AT-AT sets, but with greater size, more detail, and a little more than 2x the parts.
It's intended to be a serviceable and hopefully well-proportioned "UCS" AT-AT for people who don't want to break the bank.
Thanks to Legolijntje for creating the .pdf instructions.
UPDATE (Mar. 14, 2017): Updated instructions (V6) now available for download. This version corrects a few minor issues. If you ordered parts before Mar. 14, 2017, 8x lbg jumper plates on the "ankles" have been replaced with 2x2 round tiles (a mod a lot of builders were making, anyway).
UPDATE (April 2017): u/FatumStultorum on reddit made a UCS sticker graphic for the model, if anyone would like to use it. It's available here: http://imgur.com/Y8IHQ4Z
(2.5 x 5 inch print size should fit tile).
As always, feel free to let us know if you have any issues with the model or have any questions.