MAJOR DEVELOPMENT IN THE MISERY TAKEDOWN!
The full DMCA e-mail has been posted by the game's creator on
Steam.
The E-mail (note that this e-mail is one sent by Steam, notifying of the takedown):

The first section that interests us is right at the beginning, where there are examples of original and infringing content. Judge for yourself.
The second, more important section is near the end, "CONTENT BEING REPORTED":
This unauthorized use specifically includes our plot, individual scenes, design, artwork, scenarios, and branding are designed to directly reference and capitalize on our copyrighted work without authorization, which is why we consider the entire podcast to be an infringing deliverable. Please be advised that GSC has not granted permission to neither Platypus Entertainment or Ytopia as well as any individuals associated with above-mentioned developer and publisher for the use of our intellectual property. Furthermore, users in the reviews section specifically refer to the S.T.A.L.K.E.R. game franchise. This is why we consider the entire game to be an infringing deliverable.
It does not need to be said, but this is
RETARDED.
None of the content mentioned in the reasoning is actually in
Misery. The games don't share the plot, they don't share locations and they don't share whatever the fuck they mean with "design", "artwork" or "branding". In essence, based off the e-mail, they are trying to copyright Soviet aesthetics of Khrushchevkas, run-down military installation, villages and fucking CAMPFIRES. This is included in literally HUNDREDS of games. For example GSC could as well sue Activision for including Pripyat in their 2007
Call of Duty.
However, the cherry on the cake is the second-to-last sentence, which says, and I quote:
Furthermore, users in the reviews section specifically refer to the S.T.A.L.K.E.R. game franchise.
It just speaks for itself.
The Predditors over at r/Stalker are already in full damage control mode, claiming the e-mail is faked, is badly translated (as if a lawyer couldn't speak English) and your average run-of-the-mill accusations that don't have anything to do with the DMCA.
And then there are the ones who suddenly say it's SNCA, because it's not going in their favor anymore.
I will definitely be monitoring this situation closely.