When pressing the Super Secret Settings button in main menu options screen, it plays the sound, but with the console open you can see it does not load a shader.
It only works per world/per game load. (IE will only work if you press it when paused in game, and will only last 'til it's closed)

NOTE: This is possibly a duplicate, but other reports set to "resolved" with no actual resolve, and the reports weren't worded the correct way to explain that it was only working in game(if that makes sense)

(See attached for console log)