Launched in 1984 by Brøderbund and Ariolasoft for Apple II, then adapted on other computers and consoles of the time, Karateka is a videogame title of yesteryear, forerunner of the fighting game genre with horizontal scrolling gameplay. Inside a easter egg which is worth reporting.
Fantastic Easter Eggs and Where to Find Them: Karateka on Apple II
This is not an extra layer or encrypted messages inserted into the code by the developers: inserting the game disc backwards, starts with the screen upside down, mirrored vertically. The demonstration in the video below.
This is not a new discovery, but the video shared by the channel Geek with Social Skills unearths one little pearl perhaps known to a few. It was its creator who wanted to include it in Karateka Jordan Mechner, which a few years later would give life to a much more famous production destined to mark the evolution of the platform genre: Prince of Persia. It was not inserted secretly, but with the complicity of the publishers, enjoy the idea of being able to receive requests for assistance after the disc is inserted incorrectly by the players.