Asuka & Asuka

Earth is invaded by a force called the Galaxy Highters in 1996, which was set in the future seen from the game's release in 1989. With their abilities in space time manipulation, the Galaxy Highters are able to invade several time lines in Earth’s history and occupy each one simultaneously. In order to stop them, Earth’s militaries design the "Flying Bird" (or "Asuka" in Japanese), a jet fighter capable of time travel, enabling it to fly into occupied time lines.

Asuka & Asuka is a vertically scrolling shooter in which each stage represents a certain time zone and has its own set of enemies in the air and on the ground. The first stage is a modern day port city with futuristic enemies, the second is a prehistoric landscape with dinosaurs shooting fireballs at your ship, etc.

Power-ups are rare and come in the form of flying containers. Your weapon, represented by double rockets at first, has a limited range that can be upgraded with such a power-up. This is also displayed by adding a third rocket to each shoot.

The end of each stage features the usual level boss, designed to fit the actual time zone of the stage. When you defeat it your ship speeds up in preparation for the time warp to the next stage and you get the chance to increase your score by defeating non-firing swarming enemies in a "kind of" bonus stage. However this is still part of the level and touching these enemies still results in a crash.