It is known for the length of its games (often greater than six hours) and its in-depth strategy (including military, politics, technology and trade).

[2][3] As of 2024, its compelling gameplay and enduring popularity have been hailed by Nerdist and Polygon as one of the "greatest board games ever made.

"[4][5] Since its release, the Twilight Imperium franchise has also expanded into six novels published by Aconyte Books, tabletop role-playing games such as Embers of the Imperium produced by Edge Studios in the Genesys RPG system, and spinoff games including Twilight Inscription and Rex: Final Days of the Empire.

It is set in the unstable power vacuum left after the centuries-long decline and collapse of the previously dominant Lazax race.

[9] Players assume the roles of rising empires on the fringes of the galaxy, vying for military and political control, until one finally becomes sufficiently dominant to take over as a new galactic emperor.

Fantasy Flight set up demos of the game in a high-traffic corridor to garner more attention, and ended up selling out of all of their available copies in under two days.

[10] The game box proved to be so large that wholesale distributors had to purchase custom-sized shipping cartons in order to make them fit.

The original plan for the game was to seek funding on the crowdsourcing website Kickstarter, releasing a product with an MSRP of approximately US$250.

Ideas pitched for this version included featuring only the six original races but each with unique ship designs, as well as presenting Mecatol Rex as centrepiece figure instead of a tile.

The revised version included all previous species introduced into Twilight Imperium, and was released at Gen Con in August 2017.

The map is built from hexagonal tiles, each showing up to three planets, empty space, or a red-bordered system containing an obstacle (with additional types added in the expansions).

[14] Additionally, each faction has distinct characters and themes, and they each specialize in particular areas of the game, such as trade, combat, technology, or politics.

[13] Faction list below: Play consists of up to 9 rounds (though usually less, depending on how quickly players gain victory points) -- each of which contain several turns.

[15][16][17] It stems from a fan-version of the third edition game called "Shattered Ascension" that was built in Tabletop Simulator in 2011 using the same components but a variant ruleset and gained a significant online community.

[16] After the publication of game's fourth edition in 2017, a similar Tabletop Simulator implementation was created in 2018[18] and is now used for online tournaments.

[2] Fantasy Flight Games released a second expansion called Shards of the Throne in May 2011, with additions including new factions, technologies, scenarios and units.

The Codex is the official web based publication, published by Fantasy Flight Games that highlights rule updates and showcases new content for Twilight Imperium Fourth Edition and eventually the Prophecy of Kings expansion.