I was setting a high score in Pokémon Pinball: Ruby & Sapphire, so of
course I left it on
Maybe your Game boy was susceptible to electromagnetic interference emanating from some of the aircraft's control systems. This is a typical sort of problem a microprocessor based design could suffer from.
Ironically, those pieces of equipment that can suffer from this sort of interference (we call it susceptibility) are almost certainly capable of "leaking" out EMI (electromagnetic Interference) that can, if we choose to believe all the warnings, interfere with an aircraft's control system.
This means you've probably admitted to one of the most serious crimes I've ever seen admitted-to on SE.EE. Your parents should take the rap of-course if you were too young. Interesting reading on Quora from a pilot.
Here's another quote specifically about game boys: -
I had fuel indications on the FMC going crazy on board the B737, that
returned to normal when all electronic stuff in the back was switched
off. I suspect a "Gameboy" electronic game device to have interfered,
but this is no more than a guess. No, I did not ask to switch the toy
back on again and investigate more in depth as I was responsible for
the safety of 140 passengers and this would have been extremely
irresponsible! This is not a situation in which to do such testing!
This [ever-present responsibility accounts for why] there is no
"proof" of the relationship.
Taken from here