Sega's Game Gear arrived soon after in 1990/1991 featuring a 160x144 LCD with 4,096 colors (32 at a time), while Nintendo's Gameboy Color ... overlay sheets to display color, though the screen ...

For comparison, an iPhone 16 has a 2556x1179 display. To be fair to the Game Boy Color, it does boast a range of 32,768 colors, a vast improvement over the original Game Boy's monochromatic display.