Actually, with regards to the Donkey Kong 3 score, I believe that a score of 2.1 million is achievable based on 1 extra life at 30,000 (or whatever points level).(posted 9465 days ago)DK3 only increases its difficulty level up to the point that I am now reaching in the game. After this, the game only present 1 of 5 different attack patterns, which can be easily learned.
While I agree that the 2.1 million score was likely achieved with the game awarding repeated extra lives (whatever the factory defaults were set to), the fact that the score would not be possible without the additional extra lives had not entered my mind.