Click on options, Network, input username and password, and click sign in.
Successful login to Hidden achievements server so I can download the DLC
I tried logging in to the game to get my DLC but it gave me an incorrect username / password message. I reset my password on the website and verified that it was working and was successfully able to login to your website but when I went back to the game it still gave me the same incorrect username / password message. My game just updated to version 1.1.0 so I don't know if this is a bug or a server issue or what. I could not select this version in the drop-down box so I selected the highest version I could but it is version 1.1.0