> > ConsumerX inserts the cart into his GBA, and powers on.
> > The game code checks the cartridge it is being played on for the
> > unique ID number it was compiled to check for.
> > If the cart's unique ID number is the same as the game's unique ID
> > number, the game starts.
> > Else, the game will lock up.
>
> takes about 10 minutes to be cracked ... at the max ...

It can be prolonged. I'm with the list in that I feel that a serial ID
system will only work for games which are low-profile enough to not get
cracking attention.

That said, I feel it important to point out this essay. (Gamasutra,
registration required)

http://www.gamasutra.com/features/20011017/dodd_02.htm

This is written by Gavin Dodd, and describes the copy protection implemented
by "Spyro: Year of the Dragon". Apparently, it was a cracker's nightmare.
Also, I believe I remember someone from RISC (a well-seen
couriering/cracking group from the time) commenting on the extreme
difficulty of cracking the original StarCraft container format; that may
bear some looking into (unfortunately, I have no linkage for that).