King's Bounty: Crossworlds is a standalone expansion for King's Bounty: Armored Princess and requires the original game to play. In addition to all content from the base game, the expansion contains an additional two campaigns: Champion of the Arena, focused on combat on a number of arenas on a small map, and Defender of the Crown, a short campaign on four new islands. An editor, complete with help files, can be found in the game folder.
The expansion adds new features to Armored Princess: 9 new units, 70 new items and sets, 50 new skills and abilities, 13 new spells, some very powerful, a new dungeon, and a network of academies to improve the units for a cost. The Orcish race gains units able to exploit their new feature, Adrenaline, which makes them more interesting to play.
The gameplay is improved, the player can now cast two spells per round, more units have an influence on other units, and some spells and bosses have been imported from the original King's Bounty: the Legend.