Decay Theory
Watch the ground dissolve beneath your feet. Atom by atom.
Decay Theory is a hard-sci-fi platformer where the entire world is composed of individual simulated atoms decaying in real time. You play Erwin, a quantum cat navigating a world that is literally evaporating at the subatomic level — and you learn real nuclear physics by feeling it, not by reading it.
What makes it different
The world decays as you watch
Every tile is thousands of simulated atoms with a real decay probability. Platforms erode into swiss cheese and crumble under your feet — stochastic, beautiful, and deadly.
Quantum powers
Observation collapses a wave function to stabilize ground; Time Rewind undoes a fatal step. Later powers — superposition, entanglement, tunneling — each teach a real concept.
Erwin, a living particle system
Your cat is rendered as 2,000+ particles. Coherence is health: take damage and Erwin literally comes apart at the seams.
Real isotope data
Isotopes carry authentic half-lives and decay chains, color-coded by family. The Geiger-counter audio tempo tracks the local decay rate.
Tight, skill-based platforming
Precise tilt-and-touch controls, checkpoints, and speedrun-friendly level design. A real platformer, not a quiz with jumps.
Premium, not predatory
Free Episode 1, one-time unlock for the rest. No ads, no loot boxes, no energy systems, no tracking.
Under the Hood
- Architecture: Godot renders; a Rust core runs 100% of the atom simulation.
- Performance: tens of thousands of active, decaying atoms at a smooth frame rate on mid-range phones.
- Powers: quantum mechanics turned into verbs — observation, time rewind, and more.
- Platforms: iOS and Android first, desktop (Steam) to follow.
FAQ
What is Decay Theory?
A 2D side-scrolling platformer where the entire world is made of individual atoms undergoing radioactive decay in real time. You don't see platforms vanish in bulk — you watch the ground dissolve atom by atom beneath your feet.
Who is Erwin?
Erwin is a quantum-coherent cat — a nod to Schrödinger — whose body is itself a particle system. Health is 'quantum coherence,' shown as particle density: a healthy Erwin is a tight cloud; near death, a ghostly shimmer.
Does it actually teach physics?
Yes, through mechanics rather than lectures. Decay modes, half-lives, decay chains, fission, and reactor control are things you feel. Isotopes use real half-lives and color coding.
How is it released?
Episode 1, 'Ground State,' is a free vertical slice — no ads, no IAP. The full game (more zones and powers) unlocks via a single one-time purchase.
When is it out?
Episode 1 is the current milestone, targeting iOS and Android first, with a desktop (Steam) port later. Follow Such Software for the launch.