[1][2] Players are given control of a spacefaring empire in the distant future, and are tasked with conquering star systems using military, economic and diplomatic means.

A package combining the original game with the first two expansions was released at that time, with the title Sins of a Solar Empire: Trinity.

[9] Sins of a Solar Empire is a space-bound real-time strategy game in which players control one of three different races: the industrial TEC (Trader Emergency Coalition), the psychic Advent, or the alien Vasari.

The game features a sandbox mode, allowing the player to choose different types of solar systems to unlock achievements.

Ironclad Director Blair Fraser asserted that the game's Iron Engine is specially designed with technologies that allow it to handle very large differences in size, scale, and distance.

Credits are the general currency used by the three races in the game, and are gained by completing missions, collecting bounties, creating a trade network, and taxing planets.

A Black Market feature allows players to convert unneeded Metal and Crystal into Credits or vice versa.

Logistical structures include asteroid mines, ship factories, trade ports, research laboratories and cultural broadcast stations.

Tactical structures include orbital weapons platforms, repair centers, strike craft hangars, and superweapons unique to each playable race; for example, the TEC can build the Novalith Cannon, a giant railgun capable of bombarding distant planets.

The expansion's most notable aspect is the addition of starbases – immense defensive structures with significant firepower and various special abilities.

In addition, there are pirate bases, which are abnormally durable and well-defended asteroids that have no resources but provide a boost to tax income.

Furthermore, there are several different spatial anomalies (more commonly known as uncolonizable objects) found in the game which serve as obstacles and hazards to all players.

These include ice and asteroid fields, which reduce weapon accuracy; gas giants, which can cause dangerous explosions if a ship is destroyed nearby; stars, which allow for interstellar jumps but have large gravity wells that are slow to traverse; and various forms of space junk, which do not affect ships directly.

In addition, DLCs have added traveling hazards such as plasma storms, random rebellions, economic downturns and coronal mass ejections.

Pirate forces are, with one exception, TEC frigates, cruisers, orbital defense platforms, and mines (and the only exception still bears a similarity to Trader ships), but they are all unshielded, have heavier armor, often have their armament switched to autocannons, and are heavily customised with spikes and stylized holographic "Jolly Rogers".

The expansion also sees a noticeable increase in pirates' strength, and their bases are now outfitted with mines and TEC-issue repair platforms and strike craft hangars.

For example, an alien artificial intelligence can increase economic efficiency across the player's empire, while an ion field technology can fortify planets against attack.

Frigates are small, cheap and, individually, weak vessels that fill basic combat and reconnaissance roles, including long-range support, planet-bombing, and the colonization of new worlds.

Civilian ships are unarmed and, except when a certain TEC technology is researched, unarmored, making them vulnerable to enemy attack.

Sins of a Solar Empire was released without any form of copy protection, but a product key registered to an Impulse account was required for updates and multiplayer in the original game.

Sins of a Solar Empire's Iron Engine offers size and scale technologies that deliver large stars and planets next to comparably small orbital structures, starships and strike craft.

The engine features bump mapping on planets and ships, specular lighting, dynamic fractal generation for stars and clouds, and bloom.

[11] Sins of a Solar Empire includes various customization features, among them a level editor that allows players to generate maps for both single and multiplayer use by setting their general properties.

In addition, the base game and the first two expansions are available in a combination package entitled Sins of a Solar Empire: Trinity.

Stellar Phenomena was released on November 6, 2013, and adds interstellar hazards such as black holes, pulsars, coronal mass ejections and neutron stars, which have various impacts on combat and exploration.

Outlaw Sectors was released on June 22, 2016, and focuses on Pirates, Black Markets, and Planetary Militias - NPC factions that can assist the player in conquering their enemies.

[21] Ironclad Games added multiplayer to its early access preview in February 2023, with promises to add further factions throughout the year.

Criticism has been focused on the lack of a single-player campaign, sporadic game crashes when played online, and the potentially lengthy game-play times.

[31] In September 2008, Stardock's CEO, Brad Wardell, stated that Sins of a Solar Empire had sold over 500,000 units, with 100,000 of those being download sales, on a development budget of less than $1,000,000.