Garry Newman's DayZ meets Minecraft game Rust has been a spectacular success.
In an interview with GamesIndustry International, Newman said Rust, which went on sale on Steam as an Early Access title on 11th December 2013 priced £14.99, took just a month to make 40 per cent of previous release Garry's Mod's total after nine years on sale.
GMod has shifted a whopping 3.5 million copies, according to GI, generating over $22 million in revenue.
"Yeah - we never, ever expected anything to dwarf GMod's success," Newman said. "We can't really believe it."
Then, in a tweet, Newman said that figure had risen to 55 per cent, and relates to profit, that is, the money made after Valve takes its cut.
Rust is currently the top selling game on Valve's digital platform, outselling DayZ, Counter-Strike: Global Offensive and Starbound.
Newman promised to continue to work on Rust as long as it brings in the cash, but it's just one of four or five projects the 15-person Facepunch Studios is currently working on.
"As long as Rust pays our wages we're going to keep working on it," he said. "Even when it's 'finished', it's not finished, it'll still be updated, in the same way that Garry's Mod did. I suppose it's the way with big games, there's never an end point, it just evolves."