is a vertically-scrolling doujin shooter by AQ Loop released at Comiket 74 for Windows PC. Players take the role of one of three pairs of characters, one character being present during a given time but they can swap places with each other, and weave through a series danmaku
across multiple stages. Each duo has a "Balanced", "Attack", and "Defense" styles that affect their attack power and their ability to use special attacks. The game also features branching paths at certain points of the game that can affect the outcome of the story.
A fan-made English patch by Tenka Seiha can be downloaded here
See also Twilight Insanity
, this game's predecessor, and Alternative Sphere
, a prequel to the series.
TWilight refrAIN features examples of: