Screen Resolution
The original Game Boy system had a reflective LCD screen 160 by 144 pixels big, and recognized four colors ranging from light to dark olive green. The Game Boy Advance SP had a reflective color LCD screen 240 by 160 pixels big with a full-color display.
Sound
The original Game Boy relied mostly on MIDI sound files and occasional white noise emitted from a mono speaker, but had a headphone jack for a stereo sound experience. The Game Boy Advance SP had more sophisticated sound files, but lacked the built-in headphone jack. Both had a volume control on the side of the device: a wheel for the Game Boy and a slider for the Game Boy Advance SP.
Controls
The original Game Boy had only four buttons -- "A," "B," "Select," "Start" -- and a directional pad to control game play. The Game Boy Advance SP had similar controls, with "L" and "R" buttons on the upper-left and upper-right corners of the device for more sophisticated game play.
Power Supply
The original Game Boy ran on the power of four AA batteries that needed to be replaced semi-regularly. The Game Boy Advance SP had a built-in rechargable battery pack that could last for at least 10 hours of continuous gaming.