Probability 0 is a downward-scrolling infinite arcade platformer. Descend: enemies grow more numerous. They will destroy the floors beneath your feet; spit death at you; and cannibalize and infect each other in their mad swarming. Descend: as you combat the darkness, improve yourself. Build yourself up as a star-flinger or a teleporting menace. Come tantalizingly close to invincible, but you'll never quite get there. Descend: and die, as you did last time and as you will next time. But get deeper.