Answer: Fairchild Channel F
We're expecting Easter eggs – pieces of code hidden by programmers in applications and left as a surprise to users ̵
The first known easter egg in a video game console was found in a game for the Fairchild Channel F. Fairchild Channel F was a second generation game console released in 1976 by Fairchild Semiconductor. Other consoles of the same generation are the Atari 2600, the Magnavox Odyssey and the Mattel Intellivision.
The Fairchild Channel F was unique in many ways. It was the first cassette-based, programmable ROM game console and it was the first game console to use a microprocessor. The console also had a "hold" button – the first appearance of a pause-like feature on a video game console – users could press the Hold button, indefinitely freeze the action, and revert to it at a later date. The hold function was not as sophisticated or useful as a save game feature, but was unique at the time.
In addition, the Fairchild Channel F may also feature the first known Easter egg in a console video game. The system had 2 built-in games, 26 cassette-based games and 2 demo tapes. Cartridge No. 20, Video Whizball was a pong-like game in which you threw a ball over a field into an opponent's goal. If you're playing a series of games where the match ends on a certain level with a certain score, you can make the surname of the programmer, Reid-Selth, appear in the middle of the field as an in-game object for your balls could bounce off (he also hid his daughter's name, Tracy, in the last five bytes of the software code).
Less interactive and on Democart # 1 for the system, there was an easter egg that would print the name of the programmer – MICHAEL KT GLASS – If you held down the 1 + 3 + 4 keys and released them at the same time after the demo ended.
Since then, video game Easter eggs have become ever more sophisticated, ranging from subtle references to other video games to all mini-games hidden in the host game.