The Game: Defend Earth from the comets! Halley’s Comet is on a collision course with Earth, and it’s teeming with evil aliens bent on destroying humanity. They attack the player’s ship in endless waves, even building walls in space that the player can collide with before they realize what’s happening. Power-ups can be revealed by blasting away at meteors, though catching them and accumulating their firepower in the middle of a fierce firefight is a skill unto itself. Smaller comets plunge toward the Earth at lightning speed. Any alien ships or comets that the player doesn’t destroy keep going and attack the planet; if too many are allowed to strike at Earth directly, or if the player runs out of ships, the game ends. (Taito, 1986)
Memories: An interesting take on the slide-and-shoot genre, Halley’s Comet finally addresses what happens when dive-bombing alien invaders zoom past the player’s ship at the bottom of the screen – they keep barreling toward whatever the player was protecting in the first place. This raises the stakes nicely and holds the player accountable for any stragglers who slip past the defenses, something that most shoot-’em-ups since Space Invaders (which ended the moment the invaders landed) didn’t bother to do.
And what are those nasties doing once they slip past? There’s a gauge on the right side of the screen which not only charts the player’s progress from Earth to Halley, but it also serves as a graphical “health” gauge for Earth itself. As more bad guys pummel the planet that the player’s supposed to be protecting, the Earth accumulates glowing, burning craters on its landscape, until finally the entire planet is laid to waste. It takes time for this to happen, so it’s not something that will cut the player’s game short suddenly if they’re unaware, but it is a neat little thing to have.
Taito licensed Halley’s Comet to a U.S. manufacturer, having already downsized their Stateside operation in the wake of the 
1982–83 industry crash, but in recent retro compilations and even soundtrack/sound effects CDs, Taito has claimed Halley as part of its own lineage. Its original release date is indicative of the game being targeted at the wave of comet-mania 
that gripped the world during Halley’s close pass by Earth in ’86, an event marked by the launch of an international fleet of unmanned spacecraft to study the comet. Why none of these space probes tried to defend Earth from the comets and save us all the trouble remains a mystery.