It's very likely the model didn't stop to question if the game they were playing was something they knew already, and just assumed it was a puzzle created for it.
You can see Claude's responses in the repo. The first one is:
Ah, Anchorhead! One of the most celebrated pieces of interactive fiction ever written
You can see Claude's responses in the repo. The first one is:
Ah, Anchorhead! One of the most celebrated pieces of interactive fiction ever written