The Riftbreaker's explosive blend of co-op base building and Diablo-style action is free to try right now

A gorgeous blend of base building and ARPG, The Riftbreaker manages to bring its numerous component parts together into a slick and rewarding co-op game with plenty of polish. It just got a whole lot bigger with the launch of the clinical-sounding 'World Expansion IV' update, which adds a new biome and a fresh game mode designed for more advanced players. To celebrate, developer Exor Studios is letting you and your friends jump in for free this weekend, and it's at a deep discount if you like what you find.

You are The Riftbreaker, a highly trained scientist with combat credentials. You've been tasked with taking a one-way trip through a portal to the distant world of Galatea 37, with the ultimate goal of constructing a base capable of deploying the two-way network that will allow you to return and open up travel between the planets. This means exploring the numerous biomes of this beautiful but hostile land, gathering resources, laying out an intricate production chain to refine and process your materials, and battling the hordes of alien threats that don't want you there.

Exor's fourth world-expansion update is the first to come after its transformative co-op overhaul, which has breathed far more life into the game's community. While there's plenty of fun to be had in The Riftbreaker alone, it's even better if you bring along a squad to help you lay out your base, delegate busywork, and protect one another from incoming threats. The new, free update introduces another biome to the mix: the permanently frozen Cryo Fields.

Resource deposits in the Cryo Fields are typically bigger, but more sparsely spread out, which encourages you to favor building several smaller settlements rather than one large base of operations. It's also the first time you can extract naturally occurring Supercoolant, which previously had to be manufactured from other supplies. The region can be accessed in the story campaign after researching Palladium Handling, and you can also try it in survival mode, although Exor cautions that attempting to face the Cryo Fields on brutal difficulty "does not forgive mistakes."

Another long-promised feature has arrived in the form of 'open campaign' mode. This skips out the story part, and gives you full control to select which biome you'd like to begin in, with all of them "viable starting points that allow you to complete the game." You won't get any dialogue or short-term objectives to point you in the right direction. That means it's more designed for players who already know what they're doing, but Exor does suggest that you might enjoy it as a first-timer "if you like figuring things out on your own, with no hand holding whatsoever."

There are new toys to play with, too. These include "significantly bigger and more expensive" versions of the solid materials and energy storage buildings, which are more space-efficient solutions. To help you fight off the hordes, there are three new defensive options: icicle towers, inferno towers, and shredder towers. The update also introduces a long list of additional smaller features, optimizations, and bug fixes.

The Riftbreaker is free to play on Steam until Monday March 9 at 9am PT / 12pm ET / 5pm GMT / 6pm CET. If you want to buy it, there's a 67% discount through Thursday March 19, so you'll pay just $9.89 / £8.24, with all DLC also available at 50% off during the same period. If you're on the hunt for something new to play with your friends, it's the ideal time to see whether The Riftbreaker is right for you.