(j is correct) It's looking for 13 presses in like a span of 1 or 2 seconds. It's near impossible. But I confirmed working on real hardware more then once (this was my first Gameboy game, not alot of animation lol, I'm way better now, the current game I'm working on is hugeeee and full of love and polish)
Same if you go do the swim Easter egg. (13 presses near impossible.)