Blizzard Entertainment is the home of plenty of popular gaming franchises, including Overwatch and World of Warcraft, but in the 1990s, the company was focused entirely on real-time strategy titles. Having already experienced wild success with Warcraft, the company’s next move was to take the RTS gameplay from a fantasy environment to a science fiction one with a game that celebrates its 20th anniversary this year: StarCraft.

The game, like Warcraft, is a real-time strategy battle that pits three different sects against each other: the Terrans, who are humans that have been exiled from Earth, the Protoss, who are a humanoid alien species with superior technology, and the Zerg, insect-like aliens that seek to assimilate others. The game’s story is appropriately divided into three acts – one for each race – that each give a new side to the narrative.

StarCraft’s gameplay relies on first building up a home base and managing resources to sustain that base before creating battle-ready units and fighting the stage’s enemy. Each race plays a little bit differently, changing the approach that needs to be taken to meet win conditions; for example, the Zerg feature the cheapest and fastest means of building up units, but are accordingly the weakest, and must rely more on overwhelming numbers to defeat an enemy. Meanwhile, the Protoss, being the technologically-advanced species they are, feature longer manufacturing processes but produce far higher-quality battle units that can both deal and sustain more damage.

Blizzard started development on StarCraft in 1995, after Warcraft II released to much success. They actually used the Warcraft II game engine to power the initial build of StarCraft and debuted the game at E3 1996 – unfortunately, it received pretty poor reception from the audiences there and was dismissed as simply being “Warcraft in space.” Blizzard ended up totally overhauling the game, redoing the graphics and refocusing the game onto its three different factions.

StarCraft, after some delays, released for PC on March 31, 1998. It would go on to become the bestselling PC game of that year, moving more than 1.5 million copies and eventually selling close to 10 million copies within a decade. While the game’s single-player mode was praised, the online multiplayer helped define it as one of the go-to games of its era. StarCraft became one of the earliest games to be played in a professional setting, and it remains popular in that setting today.

Two expansions, Insurrection and Brood War, were released, expanding on the story and adding different units and ways to play. A port was made for the Nintendo 64 in 2000, simply called StarCraft 64; this version lacked online multiplayer, instead featuring split-screen cooperative modes. In 2010, a true sequel, Starcraft II: Wings of Liberty, released; this too was followed by multiple expansions, heart of the Swarm, Legacy of the Void, and Nova Covert Ops. In 2017, the original was remastered in high-definition.

StarCraft remains one of the top names in real-time strategy titles, and the original has been hailed as one of the greatest and most influential games of all time.