"BTOOOM!" is a Japanese manga series written by Ryōji Minagawa and published in Comic Alive magazine from 2009 to 2013. The story follows a young man named Sakuya Takayama who becomes trapped inside a deadly virtual reality game called BTOOOM!, where players use flash bombs and various other weapons to battle each other.

Key points about "BTOOOM!":

1. Genre: Action, Psychological, Thriller

2. Setting: The real world and a virtual reality game environment

3. Main character: Sakuya Takayama

4. Gameplay: Players use flash bombs and other explosives to fight each other

5. Themes: Survival, trust, morality, and the nature of reality

6. Adaptation: The manga was adapted into an anime series that aired in 2012

The series gained popularity for its unique concept, intense action scenes, and exploration of psychological themes as characters struggle to survive in this dangerous game. If you have any specific questions about the series or would like more information on particular aspects, feel free to ask!