CD Projekt says it’s been hacked by attackers who’ve been able to access its internal network, encrypt some devices, and collect “certain data” from the Polish video game company. The Cyberpunk 2077 developer says it will not give in to the demands or negotiate with the attacker, and does not believe any personal data of players or service users has been compromised.

In a tweet disclosing the hack, the company shared the ransom note left by the hackers, who claim to have accessed the source code for Cyberpunk 2077, Witcher 3, Gwent, and an “unreleased version of Witcher 3.” The hackers are threatening to release the source code alongside internal legal, HR, and financial documents “if we will not come to an agreement.”

In its statement, CD Projekt says that it has secured its IT infrastructure, and has begun restoring its data from intact backups. It says it has informed the “relevant authorities” as well as IT forensic specialists.

The attack follows the developer’s troubled launch of Cyberpunk 2077. The game released with numerous bugs and performance issues on PC, and was almost unplayable on older consoles. Sony subsequently pulled the game from the PlayStation Store and offered refunds to players, while Microsoft is also offering refunds.

CD Projekt has been subjected to intense criticism for releasing the game in what critics claim is an unfinished state. The company has vowed to address Cyberpunk 2077’s performance issues with a series of patches. It’s now facing a lawsuit from investors who claim they were misled about the game’s performance prior to release. The developer has also been criticized over reports that its employees were forced to work long hours in the months leading up to the game’s release.