Ikaruga is a bullet hell video game developed by Treasure. It serves as the spiritual successor to the 1998 title Radiant Silvergun and saw its initial release in Japanese arcades in December 2001.
The narrative follows a rebel pilot named Shinra who battles an enemy nation using a specialized fighter called the Ikaruga. The aircraft is capable of switching between two distinct polarities: black and white. This mechanic serves as the core gameplay feature, influencing both the stage design and the behavior of enemies.
Within the game's mechanics, all projectiles and enemies are categorized as either black or white. Players can absorb bullets that match their current polarity, while bullets of the opposing color result in death. The game includes both single-player and cooperative modes.