Hmm, none... not like totally broken, but my first Gameboy is missing some lines on the screen, but that's after being thrown into a wall by my cousin, dropped on a marble floor, been in a car with 122 degrees farenheight.
I believe it is a tough little - well we all thought it was small when it came - gadget.
Beware, I live!
I am Sinistar!
Beware, coward!
I hunger!
Roaaaaaaaaaar!