Empire is a turn-based 4X wargame, where players command armies of units
which they use to explore the game world, control territory, and attack
opponents. The game world consists of "sectors", which may be designated as
agricultural, industrial, etc. Control of these sectors grants the player a
variety of raw and manufactured materials, which they may use to construct
dozens of unit types.

In each round, the players submit their commands for the activities of their
units to the central server, which executes all of the commands either
simultaneously or in a sequence. Rounds can last anywhere from a few hours
to a day. As such, a full game can take much longer than modern 4X games,
depending on the size of the game world; "Blitz" games may last a few hours,
while typical games last months and larger games can take up to a year to
complete.