"Berlin '61" is a 163-page campaign book for GORE by PK Games. It is self-contained, including the complete GORE rules, then adding a Cold War Berlin setting, a pantheon of nasties to battle, and nifty weird science rules.
Haven't yet had a chance to play, and I'm a newbie so I can't tell you how its mechanics compare to previous BRP offerings, but it is a complete game. They've just released the player's companion at
Lulu.com - Self Publishing - Free.