Unity, the maker of tools and technology for video games, set off a firestorm on 12 September by announcing it will begin charging developers a new fee for games made using its software, called the Unity Engine.

From 1 January makers of Unity games will have to pay per user installation after a certain threshold is reached.

Some video-game makers accused Unity of violating its own terms of service and lamented that the new charges could threaten their livelihoods. Many game studios put out harshly worded statements urging the technology company to reconsider.

Game developers, rallying on X, began fuming immediately that any game enjoying a spike in installations due to a big sale, inclusion in a charity bundle or even just by being included in a popular subscription service like Microsoft's Game Pass, would trigger back-breaking Unity fees.

"Stop it," development studio Innersloth, makers of the hit Among Us, tweeted Tuesday evening. "This would harm not only us, but fellow game studios of all budgets and sizes...."

Another studio, Aggro Crab, called on Unity to reverse its plans, saying that it feared that its next game, set for release to the 25 million subscribers on Game Pass, could incur fees that "threaten the stability of our business."