US publisher Nicalis is under fire for its use of takedown notices against a variety of projects relating to hit indie game Cave Story.
The Metroidvania title was developed by Daisuke 'Pixel' Amaya and first released in 2004 as a freeware title, before Nicalis worked with him to develop ports for Wii and DS.
Nicalis has also developed updated versions -- including Cave Story+ and Cave Story 3D -- for a variety of Nintendo platforms and Steam.
The freeware version has since been decompiled and used to create a range of fan-made projects, including the Cave Story Engine 2, which allows users to create their own versions of the game.
However, the Cave Story Engine 2 GitHub repo has been taken down after Nicalis issued a DMCA, claiming the project uses the source code of its own version of Cave Story.
Various fan developers, and even some notable industry professionals such as Rami Ismail, have decried this move via Twitter, believing anything based off the freeware version to be outside Nicalis' rights.
"For anyone to play dirty like this with that game or its legacy just feels like a disrespect to everything it meant, and everything it helped make happen through its existence," Ismail wrote.
"I am pretty sure that includes my own career in games, so yeah, this feels personal."
There appears to be some confusion as to whether the freeware original of Cave Story has also been taken down. At the time of writing, it appears to still be available via FilePlanet and a fan-made tribute site.
It has been suggested that Nicalis' claim stems from its ownership of the IP rights rather than ownership of the original game.
A DMCA issued against a 2019 Kickstarter campaign for an Xbox One port states Nicalis' rights "include the game's title, logo, story, characters, artwork, music, and packaging." These were used on the campaign's main page and in its video.
GamesIndustry.biz has contacted Amaya and Nicalis for more information.