Imperium: Horizons is a standalone game that includes the states: Abbasids, Axumites, Latins, Guptas, Inuit, Japanese, Magyars, Martians, Maya, Polynesians, Sassanids, Taino, Tang, and Wagadu. Each of these offers a unique and challenging opponent in both multiplayer and solo encounters.

It is fully compatible with Imperium: Classics and Imperium: Legends for those who wish to expand their states even further.