By now we’re all familiar with the battle tactics in Game of Thrones: Confront your enemy head on—usually in some nicely arrayed lines—and hack at them until no one’s left alive or someone has won. It’s a tried and true method, with little in the way of actual operational depth. And as Sunday night’s Battle of Winterfell showed, it's particularly ineffective against an endless army of the undead. Spoilers ahead, obviously.