To whoever said Gameboy, you'll have to take that up with me. XD
I remember reading about this really old system called RCA or something. It didn't have color (even though color tech was around at the time), it used numeric keypads for input, and the game selection obviously failed.
Game.COM is the worst, in my opinion. It came out as late competition for the Game Boy. At this time, everyone else was moving toward advanced technology in their handhelds. Tiger made their monochrome handheld cheap and marketed it as a toy, not an electronic. For this reason, it would be found in the toy department of stores, like the Leap Frog device today.