Indie developer Chucklefish has been accused of “massively unethical” work practices by former staff members. The allegations against the studio, which also published Stardew Valley and Risk of Rain, stem from the development of Starbound, which entered early access in 2013.

Last week, writer Damon Reece published a lengthy Twitter thread outlining their experiences working on Starbound. In that thread, Reece said that they began their career in game development at the age of sixteen, spending nearly two years working on the title. They also state that they “worked hundreds of hours and [weren’t] paid a single cent for it while the company made unbelievable amounts of money off of my labour, and that of around a dozen other unpaid workers.” According to Gamasutra, since its early access release, Starbound has sold more than 2.5 million copies.

Reece’s claims have since been backed up by a number of other developers on Twitter, many of whom report working for exposure and the implication that they would be compensated for their work once the game shipped. In response to those claims, Chucklefish issued a statement, saying that “we’re aware and saddened by the current allegations against Chucklefish regarding Starbound’s early development.”