TWilight refrAIN is a vertically-scrolling doujin shooter by Eikyu 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.