Space invaders turns 40: How to play the classic game, and why people love to so much

Space Invaders, perhaps the most classic game ever made, is turning 40. The game was released in 1978, and in the years since has gone on to influence the entirety of culture. Its consequences were felt not only in games, but across various media, but across science fiction. It changed the way games worked. It was the first major game to depict its own world, rather than simulating something that already exists; it introduced central concepts, like the high score and multiple lives.