Music-riding puzzle game Audiosurf was the best-selling game on Steam for the whole of February, Valve has said.
It "topped the February sales charts for dollars and units sold via Steam", apparently, which is very impressive.
Not least when you consider that Audiosurf - in which players ride along a sprawling, Guitar Hero-style fretboard highway matching coloured blocks together in time to the music - was designed by one man, Dylan Fitterer.
It costs just USD 9.95 from Steam, and one of its more excellent features is that you can play it with any song you have on your hard disk. It also has online leaderboards for them, leading to amusing battles between friends over who is better at Girls Aloud.
"This kind of runaway success for an independent title is a tribute to Dylan's work and millions of informed gamers connecting via Steam each week," said Valve's biz-dev director Jason Holtman.
You can see what we made of it in our Audiosurf review.