The game gear was extremely lousy to use. Too small of a screen, ate through batteries incredibly quickly, the original, external battery pack (not included) was poorly made and didn't help that much either.

And the game selection early on was pretty lousy too. Sonic was only fun for a while.

People are doing amazing things with game gear hardware as of late, though. All of that addressed spectacularly.

A "wall wart" power source was a necessity.