The file
The game that started the golden age. The aliens sped up as you cleared them because the hardware ran faster with fewer sprites, and Nishikado kept the bug because it was terrifying.
It was the first game with a high score that saved, which is why kids started staying. The Atari 2600 version in 1980 quadrupled the console's sales and was the first killer app.
Sources: Wikipedia — Space Invaders