The best-selling game on Steam right now isn’t finished and features a startlingly amount of naked people.

It’s called Rust, and developer Facepunch Studios revealed today that it has sold more than 750,000 copies of the open-world survival game since it debuted in December. Rust is available for purchase now on Steam for $20 through that service’s Early Access program. Rust is in the beginning phases of development, but Early Access enables consumers to pay for the opportunity to playtest products before they’re finished.

Rust has players entering a hostile world with nothing. Gamers must then explore the landscape for resources to craft clothes, weapons, and shelter. At the beginning, people don’t even have pants and must run around the woods in the buff.

“We are blown away by the popularity of Rust so far,” Rust creator Garry Newman wrote in a blog update. “It doesn’t even seem real yet. Our original plan was to release on Steam Early Access, without making a big deal of it, and slowly build up a bigger fan base by releasing regular updates, until we reached a point where we felt the game was ready for a bigger audience — and then start advertising it and bringing more people in. The unjustifiable popularity is both a blessing and a curse.”

Newman said it is a blessing because the sales will help it fund further development.

“We’ve been the No. 1 best seller for two weeks,” he wrote.

Rust has had as many as 50,000 concurrent players, which was enough to make it the fourth most-played game on Steam.

“But it’s also a curse because the amount of people playing has kind of given us a sensory overload,” wrote Newman. “We see all these amazing things happening, voices from all directions, ideas, bugs, cheaters — and we’re scrambling to catch up with everything.”