Probability 0

Probability 0 is an infinite, downward-scrolling arcade platformer. You descend through a randomly generated pit, fighting enemies and hazards while building a character capable of reaching deeper levels. Death wipes your progress, but each run offers new terrain, enemy encounters and upgrade choices.

Descend and adapt

The pit contains dangers such as monsters, spikes and unforgiving gravity. As you descend, you improve your abilities, becoming, for example, a star-thrower or a teleporting menace. Powers can let you walk across spikes that once threatened you or punch through walls, but you can never become invincible.

The enemies grow more numerous and can destroy the floors beneath you, spit attacks at you, or cannibalize and infect one another. Some are invisible, reckless, explosive or seemingly untouchable. Their distinct behaviours call for different approaches: one moves at erratic angles, while another heads straight toward you. Boss enemies appear intermittently, and some enemies only show up deeper in the pit.

Choose your powers

There are about 36 powers, with few prerequisites. Each time you level up, a new row opens, and you can buy abilities from any row unless one builds on a weaker version of itself. For example, you need the power that reduces fall damage before you can get the one that prevents it entirely. The abilities offer different ways to shape a build, including immunity to spikes and a punch that kills any enemy in one hit.

Changing runs and music

The landscape is randomly generated, and higher-order enemies enter the spawn queue in a random order. The game offers thousands of possible builds, while death wipes everything between runs.

The dynamic music by queenjazz changes as you descend: bass layers come and go, chords swell and fade, and sirens sound as danger approaches.