Alterhavoc is a rogue-like bullet hell game where players must battle monsters to survive. The game features an inventory system where players can arrange resources in a limited area to receive additional buffs. One day, a meteorite falls to Earth, causing monsters to appear and putting the world in an apocalyptic state. In response, a group has formed a secret organization known as Heaven Diversion. Their mission is to defeat the monsters and restore the world to its natural state, thus saving humanity from destruction.