In a nutshell, Fallen Earth's acquisition by GamersFirst has necessitated that all users acquire a GamersFirst account to log into the game. Never fear, though, it's a free account, and it's just another step in the changeover process. In fact, GamersFirst's Joseph "Linus" Willmon writes that the account gymnastics are part of "phase two, where we fully integrate Fallen Earth into the GamersFirst publishing platform." Phase one has already been completed, and it involved a lot of behind-the-scenes hardware moves and the like.
This week's Fallen Earth dev blog contains a complete rundown of the rest of the changes scheduled to occur in phase two, including payment and subscription tweaks.