You’ve got a new way to blast a bunch of alien goons in spaceships while mucking around with your phone — but this one doesn’t require a download.

Big Viking Games launched Galatron today, its latest foray into HTML5 gaming. It’s available not in the app stores but on Facebook Messenger for both mobile and desktop. It’s a free-to-play app, where you take your spaceship and destroy waves of enemy vessels (both small and large) as you collect power-ups. Think of it as a sci-fi take on Capcom’s arcade classic 1942.

You can also upgrade your ships, and it has a leaderboard so you can challenge your friends on Facebook Messenger.

Big Viking recently launched a $10 million publishing fund to help third-party development of HTML5 Messenger Instant Games, so it is invested in this new, potentially $100 billion opportunity. Since these titles are HTML5, you’ll be able to experience them without having to download an app. This lower barrier of entry could attract even more players.

“Big Viking Games has been at the forefront of HTML5 development, and with Galatron we’re able to really present that technology and show what a game on messenger can look like,” said Albert Lai, the cofounder and chief executive officer of Big Viking Games. “Galatron has features and gameplay that many thought were impossible in an instant messenger game so we’re excited for players to see that and realize that this is really a viable platform for quality games.”