It looks like the puzzle-action game Qix (Taito America, 1981) hasn't been discussed on the forum, so I'll give it a brief but emphatic nod. Highly addictive---I've easily played it the most of any ACA title (runners-up Baraduke, Halley's Comet).
In the graphically-spartan Qix you are a tiny cursor moving about the rectangular perimeter of the game area, venturing into the center area to take "bites" and claim territory, cashing in the stage when you pass a fixed threshold (default 75%; exceeding this threshold in the final bite is a major source of points). Your main adversary is a randomly gyrating line-monster, the "Qix", whose touch kills any bite in progress. But you face perimeter-circling assistant "Sparx" baddies as well to ratchet up the tension and distraction, and they get more numerous and aggressive with time.
This game has features that are quite distinctive among arcade titles. Most fall under the idea of "emergent gameplay" (a feature shared with other territorial games, like Go, but also with tunneling games like Dig Dug, I suppose). This game is about as simple an engine as you could imagine to turn randomness into fast-paced excitement, and an empty board into a built environment embodying strategic ideas.
The enemy swirls about, and you try to contain it. You can take small, safe bites (but face time pressure), or big risky ones, according to your skill and appetite. (Impulsiveness and the "my own worst enemy" effect are strong factors here.) Bites are not just numerical progress---their shape and placement influences the random walk of your main adversary, potentially driving it into a desired area or shielding your subsequent bites from attack. (The enemy, in turn, has a bit of player-directed deadly bias in its random walk, and also seems to prefer to seek out larger areas to avoid traps.)
This creates an emergent concept of quasi-territory, as a built space in which you enjoy relative safety to act. But the speed of your enemy and the difficulty of containment also motivate a "disjunctive" approach, where you prepare connected areas A and B and wait to see which will end up containing the Qix. And even if it's possible to seal off B while the Qix is in A, it may be preferable to go and improve B's shape/trap qualities instead. Roughly speaking, narrow and/or spiky environments hamper the Qix's deadly movement, although spikes can impede your perimeter traversal as well.
The cursor has two drawing modes, "fast" and "slow"; fast is suitable for quick probes into the center and sketching out a territorial framework, while slow gives 2x points and is meant for cashing in larger areas. There is more to say, but given that I'm still a relative newcomer, I'll leave it at that. Fun, fun game!
Basically an Extra Lite SuperEasy diet ver, with none of the PCB/ACA's fierce (and Garegga-prefiguring) per-shot Rank.
Super cute + Super hardcore single-screen topdown blaster ala Battle City and Toy Pop. (don't sleep on Toy Pop it's rugged as fuck 
)
) and NebulasRay, but they're all a bit further from that late 80s/early 90s sweet spot.
Fuckin rickety-ass HS mode, doesn't take much to tip it over. 
