It’s more about time than it is space, not that those can ever be fully disentangled. Space only finds actuality in relative positions, and you’re not being challenged to judge the length of the gap between your cover shields or navigate a maze. If the titular were not engaged in constant horizontal motion, the game would be trivial, a Breakout  clone with the Pachinko [c. 1926] chance ricochets taken out. You’re being challenged, most dramatically and rapidly with the final stragglers, to judge the length of the gap between now and the future, as inferred from present conditions and past knowledge.
The game plays like the principles of a computer printer, but with you, the unreliable and nonlinear human, in full control. The rectangle of 55 Space Invaders is a kind of timer that counts literally “down”, and you can reach out and manipulate the rate of vertical drop by narrowing the phalanx, at the inverse cost of increasing their horizontal speed, that much ballyhooed, compellingly stressful, difficulty curve. Once that gets unmanageable, you switch to what might have been your first instinct and work on rows instead of the columns your gun is predisposed to eliminate, now playing defensively. Ah, that’s something else worth noting here: You’re defending yourself, and implicitly a larger bloc of population, against the villains that personify the game and (in iconography, in places) gaming as a whole. The game, again, essentially doesn’t want the player here. If you leave it alone, it’ll even plaʎ itself. Who’s really the invader, huh!? (I’ll leave it to those with more sure footing on post-war Japanese culture to talk about how this game might relate to their own conceptualization of death from above.)
Space Invaders  is intimately tied to that other medium what sculpts in time and math as its clay: music. The game is defined by its descending military march theme that seems to be in-sync with the Space Invaders’ every step (although in actuality, it increases in speed roughly 3 times as fast as the Invaders’ advance,) by the free jazz saxophone (or if you prefer, Van Halen guitar) squeal of the spaceship above, by the kettle whistle of your pea-shooter. How fitting that it inspired the first (to my knowledge) novelty video game song. Music and video games share a common point, also, in their cultural ability to be completely abstract and come off completely naturally, where people widely sneer at movies or paintings or whatnot that shun representative form.
The observation has also been made that playing these twitchy arcade titles are like playing a musical instrument… but in my limited experience of both, it’s so much less forgiving to perform within the strict and always-changing confines of an arcade game than it is to play sheet music. Entering the flow state here is more like a dance with the game as your partner, although it’s not a rhythm game either. Dodging the bullets does remind me a bit of Guitar Hero , but I’d like to propose that they both fall under the same larger mechanical taxonomy as bullet hells, or as Speed Race  and DONKEY.BAS , nominally driving games: the “rain game,” no matter the theming. (Obstacles cross the screen, usually down, like rain drops. Sometimes they’re random, sometimes they’re in pattern. Sometimes it’s conceptualized as you moving towards them, other times as them moving at you. Sometimes you’re meant to hit them, sometimes you’re meant to avoid them.)
Right about when you can get through a whole wave without getting hit, the nature of the game changes. The cover that once protected you is now something that protects your enemies from you. You stop having to even look at if your tank is going to be hit by a bullet, because your brain is now trained, extrapolating from the constant speed and linear path of the bullet from the place it was fired. (At least, until the bullets are showing up about half an inch away from your cursor.) You are walking the road to mastery. It’s not so oppositional anymore, though your adrenaline still pounds your hands sweaty as you question your ability to perform to the mechanical standard, though clock time falls away into game time.
Really, it’s a waste of time. But then, isn’t everything in life wasting time until we waste away? A third of life is spent sleeping, lying around literally doing nothing at all — I would consider that a pretty strong hint. Hours at a stretch are thrown into our jobs, most of which amount to nothing we care about in its own right, in exchange for the money that lets us perform the basic tasks of maintenance that takes up erratically large chunks of the rest of our time, necessary chores like eating or washing or transport or repairing. It’s a wonder we get anything else done at all; as I write this, I’m just now realizing it’s Sunday and this has to be done tomorrow, having fallen behind due to exhaustion from my day job. We largely don’t think of the time we spend at work as wasted, though: people treasure it as “productive.” Time is money.
Space Invaders sure made a lot of that money, but if coin-op games were strictly in the business of maximized profit, they’d be slot machines — or, more culturally-germane to 1970s Japan, the aforementioned Pachinko. Space Invaders in its sheer profitability alone marks, for Wikipedia at least, the beginning of “The Golden Age Of Arcade Games,” surely the truest mark of an era-defining work. (If this blog were a book, “Spacewar to Space Invaders” would be the prologue.) The arcade existed long before video games, though, already full of mechanized amusements, and when they were new in the late 19th century, there was a lot of modernist-tinged thought about what this implies for the strange new symbiotic man-machine (about which you can read more here.) A perverse, mocking inversion: laborers spend all day at work pulling levers and pushing buttons on machines to get money, and for recreation, they recreate it, giving money to machines to push buttons and pull levers.
The literal actions undertaken when playing a Space Invaders cabinet, like its forebears, are scarcely discernible from the process of operating a lathe or sewing machine, besides the outsize frenzied difficulty. It can be more taxing than our actual work, and yet we do it to unwind? The difference is that Space Invaders, and other arcade games, don’t pretend to be anything but useless. It thumbs its nose at the concept of productivity, and when you play, so are you. Well… except…
That high-score table, one of its trumpeted chief innovations, elevates the points to the point. It’s the bastion of truth, it’s the source of value greater than or equal to money, something you can be proud of. It’s the only reason to reach for that spaceship other than putting a stop to the loud noise it makes. The high score sketches the outlines of an invisible community of esteem, even potentially of those who are otherwise complete strangers to one another, communicating like a message in a bottle or a carving in a tree. You pay to join the club. We’ll see a lot more single-player experiences from this point forward, but not yet do we pass into the solitary.