Inscryption presents itself as a deckbuilding roguelite featuring Leshy, a mysterious antagonist, in a cabin setting. The first act is complete enough to seem like the whole game. Then a hidden file sequence — requiring the player to find an in-game camera, photograph specific objects, and decode a URL embedded in the developed photo — reveals that the game has a metagame layer.
The decoded content points to a fictional game developer history, a series of ARG elements, and a revelation that Inscryption’s ‘game’ was built from components of an older, dangerous game called ‘Kard Kraft.’ The ARG was designed by Daniel Mullins to blur the line between the game’s fiction and its real-world publishing history.
Players who followed the ARG to its conclusion received a communication from a fictional figure inside Mullins’s game world who appears to address the real player rather than any in-game character. The communication references the player’s system files in a way that was designed to feel alarming without accessing anything.
Inscryption is among the most architecturally complex indie games ever made — a roguelite containing a complete escape room containing a full ARG containing a meta-horror narrative.

Found this by accident on my third run. Came here to understand what I was actually looking at. Great write-up.
Saved this article for my gaming reference folder. Essential reading for anyone serious about this game.