As a result of this, several important events that occurred in the books but did not make it to the film are depicted in-game, such as clashes at Helm's Dike in front of the fortress, and the Glittering Caves of Aglarond. In Helm's Deep, Turbine chose to provide a more lore-accurate portrayal of the Battle of Helm's Deep from Tolkien's work, as opposed to the film adaption by Peter Jackson, where some details were modified or omitted. The expansion also adds modified trait trees and five new zones to explore in Western Rohan. The new expansion increases the in-games level cap to 95, and one of the main new features is the ability to fight 'epic'-scale battles such as the Battle of Helm's Deep. The Battle at Helm's Deep is created in-game using refined technologies that Turbine created during the development of the expansion, which allow for a significantly larger amount of action and character models during a session.

The expansion is available for download both on the web and on Steam. It was released on November 20, 2013, after it was postponed by two days from the original release date, due to a power outage. The Lord of the Rings Online: Helm's Deep is the fifth expansion for the MMORPG The Lord of the Rings Online. 2013 video game The Lord of the Rings Online: