The Game Boy series can be imagined as a portable version of the Nintendo Entertainment System (NES) with limited power, but you'll see that it introduced very interesting functionality.
The rainbow analysis
The immense popularity of this console led to a variety of revisions (e.g. Game Boy Pocket, Light, and even adaptations in the form of Super Nintendo cartridges). As a matter of fact, the Game Boy brand spans two generations: within the 4th generation, we find the monochrome Game Boy and its revisions, while the next generation features the Game Boy Color (shipped after the demise of the Virtual Boy).
The good news is that this article covers both ends of the spectrum. So, in the end, you'll gain a clear understanding of how the Game Boy works and how its technology evolved into the Game Boy Color.