StarCraft II: Heart of the Swarm is the expansion pack for the hugely popular real-time strategy title StarCraft II on the PC. It’s a pretty big deal for gamers and to prove the point, creator Blizzard Entertainment has revealed today that 1.1 million people tuned in to its 21-hour global broadcast celebrating the launch.

Video game live-streaming service Twitch says that at its peak, 125,000 fans were watching as Blizzard streamed its “Global Swarm Invasion” from local events held at Melbourne, Seoul, Versailles and Irvine.

Similarly, a StarCraft II: Heart of the Swarm tournament, which was held at the Major League Gaming (MLG) Winter Championship in Dallas, Texas, attracted 1.1 million viewers last weekend. At its peak, Twitch says 157,000 people were watching online.

“StarCraft II has been a premier game at Major League Gaming events since Wings of Liberty was released,” Sundance DiGiovanni, CEO of Major League Gaming said. “Heart of the Swarm has generated even more excitement, and we’re all looking forward to what the future brings for StarCraft II esports.”

Blizzard released the highly-anticipated expansion pack on March 12, adding an extra 20 missions and seven new multiplayer units. Over the launch weekend, Blizzard says it sold “approximately” 1.1 million copies worldwide, including both physical and digital versions. Even if that figure is off ever-so-slightly, we’re happy to let it slide given that it creates a trio of equally impressive figures.

Here’s a quick idea of what the expansion pack is all about:

The bigger picture here is that PC games are currently undergoing something of a renaissance. As the current generation of video game consoles get a bit long in the tooth, PC hardware is starting to show its prowess, adding a bit more grunt and polish to multi-platform titles.

MMORPGs such as World of Warcraft and EVE Online are still immensely popular, and Blizzard’s latest efforts, including StartCraft II and Diablo 3, have both been pretty successful.

All of this has fed into the popularity of esports. As the professional side of competitive play continues to grow, so does the interest in watching such events over a livestream.

Yesterday we reported how during the Winter Championship in Texas, 2.6 million people tuned in for more than 6.5 million hours of content featuring Call of Duty, League of Legends and StarCraft II matches.

Twitch is at the center of all that, giving both professional and casual players the chance to watch, learn and engage with other people who are passionate about similar games. In February, 600,000 users attracted more than 28 million unique viewers to the service.

Provided more video games and expansion packs such as StarCraft II: Heart of the Swarm come along, that trajectory won’t be slowing down anytime soon.

Image Credit: Juergen Schwarz/Getty Images