You couldn't play gb adv in the dark. My game gear I got the battery pack thingy that you recharge, 5+ hours of game play. And I also had an addon that magnified teh screen. The games did not suck imo, nba jam and world series baseball are still 2 of my favorite games.
5 hours is still pretty pathetic, especially since you had to buy a battery pack to get even that much out of it. A GBA gets around 13 or 14 hours on average. It doesn't matter if you could play the GameGear in the dark, the colors still bled together because it was back-lit instead of front-lit. You still couldn't see anything. And a magnifier to make the screen bigger? The thing was massive enough on it's own without having a huge magnifying attachment stuck onto it.