Space Invaders is the founding grammar of the video arcade: a single glowing P1-phosphor green painted on total black, every shape snapped to an 8×8 pixel lattice. Tomohiro Nishikado's 1978 Taito cabinet had no color hardware, so the whole aesthetic is one hue burning against a dead CRT tube.
The design language is beauty from the poverty of 1978 silicon — descending rows of squid, crab, and octopus aliens, a monospace SCORE / HI-SCORE HUD, eroding shield bunkers, one lone laser cannon. No anti-aliasing, no curves, no ornament: just chunky orthogonal blocks and the relentless lockstep march.