When I launch Endless Legend it gives me a code to redeem but I cant find anywhere to redeem it here. The old link I saw in a few threads https://www.amplitude-studios.com/user/edit seems to be dead. 

The old version of G2G required inputting CD keys into the site to unlock your account badges and G2G points. It was always slow as hell and rife with issues. When G2G was reworked, the CD key input was replaced with the account sync system, which is marginally more efficient. I don't believe the keys serve much of a purpose anymore.