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This appears to be a diagnostic screen, as some people have reported that it may say "TEN" instead of "ONE" on one line or the other. It is theorized that this screen displays the result of some kind of code verification algorithm or checksum, with each line representing the status of a different portion of the game's code.
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While porting the game to the NES, one of the developers snuck in a code that gave you all the powerups, due to his inability to play the game. He then forgot to take the code out.
The code later became known as the Konami Code.
The code later became known as the Konami Code.
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