Jekyll/Hyde Klondike Solitaire

Jekyll/Hyde Klondike is a proof of concept NES ROM with the purpose of behaving differently if played on FCEUX compared to other emulators. When played on FCEUX, the "Hyde" version of the ROM plays, which makes all games of Klondike Solitaire impossible to win, where on hardware or other emulators, the "Jekyll" version of the ROM plays, which has fair shuffles and is possible to win in.

An article discussing the proof of concept and how it was made is at the following link:

Using FCEUX to Play this Proof-of-Concept NES Game is a User Input - Expanding on PoC||GTFO 18:4

Title screenshot of the fair "Jekyll" version of the game
Title screenshot of the impossible "Hyde" version of the game
Screenshot of a game of Klondike Solitaire being played

Download the NES ROM

NES ROM File
Source Code [HTTP]