QIX / Taito / Arcade
I have to hand it to whoever looked at Qix and said "You know what this needs? Porn." Never would have put the two concepts together myself. Impressive vision.
But as the endless boring porn variants of it that came out of Asia made clear, Qix largely works because of pitch-perfect minimalist presentation. The enemy is a randomly moving bunch of fractal sticks that apparently escaped from Fantavision or something, but the randomness combined with the pressure from the little asshole sparky enemies driving you from safety, the usually fairly tight timers, and the complementary dark and randomly fluctuating sound really come together nicely to make a simplistic game about drawing blocks feel tense and compelling.
People would go on to try to complicate this formula in various ways to "improve" it but for my money the original got it right on the first try and doesn't need to be touched.
* Gameplay Video