Indie publisher Devolver Digital has acquired the maker of Early Access smash hit Astroneer, System Era.

The deal is worth a maximum of $40 million; $20 million is being doled out upon the acquisition closing, while another $2 million will be issued in a mix of cash and share 12 months after close. $10 million will be paid out when System Era's next game comes out, with another $8 million set to paid in cash and shares based on performance goals between the 2023 and 2027 financial years.

System Era was founded in 2014 and is behind Early Access title Astroneer. To date, that game has made more than $87 million in gross revenue and has been played by more than 13 million people. In its consumer press release about the deal, Devolver says that it nearly agreed to publish Astroneer back in 2015.

"The thing that excites me the most about System Era is the cultural and strategic fit with Devolver," the publisher's CEO Douglas Morin said.

"This is a highly experienced, talented group of developers who come with a proven hit, Astroneer, in its eighth year. Their know-how in Expandable Games development opens up a new player-base and revenue stream for Devolver. We are looking forward to bringing the fun to new players in new, innovative ways - and above all welcoming the team to Devolver in coming days and months."

System Era CEO, Brendan Wilson, added: "Devolver and System Era have been mutual admirers for a long time. We've always seen Devolver's banner as a mark of quality, but they also represent an approach to developing and publishing games that is unique in the industry. Their developer-first orientation lets bold and unorthodox ideas thrive. We're thrilled to be joining into a confederation of like-minded people where System Era's games will get the support needed to reach global audiences, and our developers will continue to work within the culture they love."