Japanese publisher Konami has issued a cease and desist against a remake of the original Castlevania in the Unreal Engine, although have said that all files currently online can remain available for the moment, at least.
Castlevania is a 1986 NES title where you control Simon Belmont on a quest to kill Dracula that has grown into one of Konami's most enduring franchises.
Konami isn't the first publisher to have to deal with fan projects: just last week Zenimax shut down long-running DOOMRL, and the annals of gaming history are stuffed full of fan projects that rise to prominence before getting slammed with a cease and desist order. In this case though, it seems Konami are being more reasonable than a lot of cases.
"They've allowed me to keep the files up for now, but all development and updates must be ceased." said the developer of the game, currently still available on Itch.io, going by the handle Dejawolf. "There's a small glimmer of hope though, Jay from Konami UK will do what he can to see if it's possible to get an official license."
There's form for cooperation between publishers and creators of fan-made projects, with Sega recently hiring the team behind an unofficial Sonic The Hedgehog 2 remaster to assist with the upcoming Sonic Mania. This would be a step beyond that however, because it'd be handing the license and a lot of the decision making off to the fans making the project, which seems like a big step, but the fact Konami have allowed it to remain online is a clear statement of interest.
You could take the fact that the game is still allowed to remain online in the wake of the splash that will no doubt be generated by the cease and desist as Konami gauging for reactions to the title, even.