Developer MercurySteam has just released its latest project: online action-adventure sci fi shooter Raiders of the Broken Planet is available to play now. In an announcement posted to their website, MercurySteam co-owner Enric Álvarez said, “Raiders of the Broken Planet is easily the most ambitious title MercurySteam has ever produced. It has taken us three years to get here and I’m so proud to be launching the Prologue and Alien Myths campaign today.”

Rather than releasing a full $60 title all at once, MercurySteam will be rolling out campaigns for Raiders of the Broken Planet one by one. As stated above, yesterday’s release contains the game’s prologue and first campaign. The game itself, containing only the prologue, is available as a free download. Each campaign is then available separately for $10 each, starting with Alien Myths, in order to ensure “the barrier of entry to be as low as possible” for prospective players.

According to MercurySteam, “In Raiders of the Broken Planet you pick your protagonist and work together with three other players in a counter-operative adventure. The biggest idea underpinning the game is something akin to Dark Souls, whereby a single player, The Antagonist, can invade a match just as it begins and choose to fight alongside the bad guys against the four-player human team. The goal of this Antagonist is stop the Raiders and prevent them from achieving their mission objectives, which change from scenario to scenario in each mission.”

Furthermore, Alien Myths – the first of the game’s campaigns – tells a more specific story: “Harec and the Raiders must find the legendary Protectors but they need the help of Shae, Harec’s old flame, in order to help him do it. Shae doesn’t trust him, though, after how things ended last time. Across four intense missions, he’ll also recruit three more Raiders: Hans, Mikah and Ginebra. Each character has dramatically different play-styles with unique abilities, weapon proficiencies as well as different strengths and weaknesses.”

Currently, there are three more planned campaigns for Raiders of the Broken Planet: Wardog Fury, Hades’ Betrayal, and Council’s Apocalypse. Players will be able to jump into a storyline whenever they choose; the campaigns don’t have to be played in order, or all together, though playing through all of them will “reveal even more about the mystery at the center of the Broken Planet.”

Raiders of the Broken Planet is available now for Xbox One, PlayStation 4, and PC. You can check out this year’s Gamescom trailer for the Alien Myths campaign below.