Steam Early Access game Space Engineers has sold one million copies since its release in October last year.
The Czech Republic-based team is continuing development of the game before a full release, having already made some 50 updates to the title on a weekly basis since launch.
“We feel twice as happy with this achievement since it came on our first year anniversary since Space Engineers was launched to the public. This gives us double reasons to celebrate,” said Keen Software House CEO Marek Rosa.
“We want to devote this accomplishment to our fans, whose encouragement and active participation made this possible. They have been beside us all along, giving inspiration for new ideas and supporting us with their valuable feedback. It is a great thing to have such an amazing community like ours."
Space Engineers is a sandbox game that tasks players with the construction and maintenance of space stations and space ships, which can then be piloted and used for asteroid mining, amongst other uses.