
In addition to new art and gameplay elements, the creators of Horn of the Abyss have added a variety of duplicates of old objects on the adventure map, mostly those that fit better in certain environments (for example, an icy underworld gate in a snowy landscape). The add-on expanded the number of creature storages in which the hero fights with the guards in order to obtain resources, artifacts or warriors. A series of seven objects called warehouses was introduced, when visiting which the player receives a certain type of resource every week (unlike the already existing weekly generators, the number and type of resource for which are always different). One of the game objects, the Cannon Yard, allows you to purchase a cannon - a fighting machine from the forge of the new city of Quay. Horn of the Abyss adds many new playable and decorative objects to the adventure map in Heroes III. In the current version of Horn of the Abyss, three campaigns are available, connected by a common story.

The developers have planned the release of a trilogy of campaigns, the plot of which is based on the Horn of the Abyss artifact. The plot of Horn of the Abyss covers the setting of the original Heroes of Might and Magic III and unfolds in parallel with the events of the Armageddon's Blade add-on.
