What did you try for the Konami ending? put it in as a spoiler.
Not sure how to spoiler when this site doesn't have a spoiler option, but alright.
I tried pressing the up arrow twice, down arrow twice, left, right, left, right, B, A, and Enter. Some variants I did include adding another B-A sequence and using space instead of enter. I did this on the instructions, the main menu, and in-game.