The Internet Archive has an incredible free collection of 1980s handheld game console emulators. In 1978, my brother and I played the hell out of Coleco Electronic Quarterback. It's amazing how compelling and addictive a flashing array of LED dashes was back then, and still is. From the Internet Archive:
This collection of emulated handheld games, tabletop machines, and even board games stretch from the 1970s well into the 1990s. They are attempts to make portable, digital versions of the LCD, VFD and LED-based machines that sold, often cheaply, at toy stores and booths over the decades.
We have done our best to add instructions and in some cases link to scanned versions of the original manuals for these games. They range from notably simplistic efforts to truly complicated, many-buttoned affairs that are truly difficult to learn, much less master.
They are, of course, entertaining in themselves – these are attempts to put together inexpensive versions of video games of the time, or bringing new properties wholecloth into existence. Often sold cheaply enough that they were sealed in plastic and sold in the same stores as a screwdriver set or flashlight, these little systems tried to pack the most amount of "game" into a small, custom plastic case, running on batteries.
They also represent the difficulty ahead for many aspects of digital entertainment, and as such are worth experiencing and understanding for that reason alone.