
Flagship has just announced that they will be holding the Beta period in grace for yet another week. 21st of November is the last (last) day of the Beta. Accounts that has not been activated by a registration code by then will be suspended. I would assume it is still possible to reactivate the beta account after 21st, but it will at any rate not be possible to play without registration.

Before Flagship Studios, there was Blizzard North. Originally known as Condor, the Redwood-based studio was acquired in 1997 by Blizzard Entertainment. At the time, Blizzard North was hard at work on the development of the game that would be the cornerstone of everything that came after: Diablo.

IGN : Remember Hellgate: London? The dark fantasy action role-playing game came out in 2007 for PC, a year before developer Flagship Studios went bankrupt. Since then, various free-to-play and online revivals have come and gone. Now, 17 years after the release of Hellgate: London, it’s back.
I remember some friends and I all bought Hellgate: London day one because it was made by some original Diablo devs. We had fun playing it, good memories.

PC Invasion: Hellgate: London is back on Steam, but it's not what you expect it to be. It's a single-player game in the vein of Asian MMOs.