Yeah, bugs in software gets to be a pain.
Maybe those bugs were the reason why Nintendo didn't release the Lost Levels in the U.S. (Too hard for Americans, my foot!) Some bugs can be exploited, though, and I guess that's good. : )
Not all bugs can be completely avoided, even by a company like Nintendo. Also, some older games are becoming more and more buggy due to the deterioration of the boards inside each cartridge. My Zelda II cart is barely playable, and it's probably 12 years old. It is a pity that video games have such short lives...
"I wish that it need not to have happened during my time," said Frodo.
"So do I," said Gandalf. "And so do all who live to see such times. But that is not for them to decide..."