RedLynx racer Trials HD has surpassed one million sales via Microsoft's Xbox Live Arcade service.
The game originally launched last year as part of Microsoft's Summer of Arcade promotion and has since been joined by the Trials HD Big Pack expansion.
"Only a handful of downloadable console games have reached this plateau," said Tero Virtala, CEO of RedLynx.
"For a company of about thirty-five people, it's a significant achievement, and it validates our strategy of focusing on online and downloadable games that have the potential to evolve into long-term, successful game franchises."
A second expansion pack, Big Thrills, is expected to be released before the end of the year, and includes tracks created by the Trials HD community.
A recent interview with RedLynx CEO Tero Virtala from earlier in the year, can be read here.