Gears of War: E-Day’s Horde Siege mode is presented as a major reinvention of the series’ familiar survival format, using larger maps, objectives and exploration to create something closer to a standalone co-operative game. Although the writer found the mode promising and potentially the most interesting part of E-Day, a poorly run preview event limited playtime and left important questions unanswered.

Instead of defending one small area through fixed waves, four-player squads move across open, multi-objective maps centred on a device called the R.I.G., completing tasks such as luring or defending against Locust forces. Optional objectives grant temporary Squad Perks and Weapon Parts, the latter retained only if players extract successfully; extraction involves surviving a three-minute helicopter holdout and resembles recent Call of Duty Zombies systems. Multiple squads operate simultaneously across each map, adding a larger-scale element, but the writer was able to play for only a little over two hours because of authentication and build-encryption problems.