Atsushi Ishida

The enemy is a self-replicating network alien. It hangs from a membrane at the top of the screen and grows down towards your ship — and its growth rules come from network science. Scale-free growth breeds hubs, small-world growth hides shortcuts, proximity growth knits a dense mesh, and hub-and-spoke growth hangs everything on a few hubs.

How it plays

Move with the arrow keys. Hold Z for the machine gun; hold X to charge a piercing beam that destroys a whole column.
Anything no longer connected to the membrane falls away at once. Each species has a different weak point, and the weak point comes from its structure — find the cut that brings the most of it down.
In Training you meet the five species one by one. In Deploy you face the Mutant: it changes species every 20 seconds at shifting spots, its leftover colonies keep growing, and after two rounds it starts learning to send more often the species that last longest against you.

A run takes a few minutes. Keyboard only (not for mobile). English and Japanese — press L to switch.

Behind it

There's a design note (PDF, in the downloads) on how each rule was designed from ideas in network science: which mechanism each species keeps from a known model, why each species breaks differently, and the bandit-style rule the Mutant uses to learn. The whole game is a single HTML file with no external dependencies; all the visuals and sounds are drawn and synthesized in code.

The code was written with Claude Opus 5.5 (Anthropic) under my direction. The concept, design decisions and play-testing are mine.

Feedback welcome

I'd love to hear how long you held off the Mutant and which species it rated toughest for you (both are on the results screen) — and anything that felt unclear or unfair. Thanks for playing!

itch.io Community » General » Release Announcements · Created a new topic Entropy Janitor — a free browser puzzle game where you tidy up against entropy

Atsushi Ishida14 days ago

Hi everyone! I've just released **Entropy Janitor**, a short, free puzzle game you can play in the browser.

**Play:** https://aishidajt9.itch.io/entropy-janitor

**The idea**

In most puzzle games the enemy is a pile of blocks. Here the enemy is the tendency of things to get messy on their own. Coloured particles keep mixing by themselves, and you work for the Entropy Janitor — a very serious public office — tidying up a small universe until it reaches heat death.

**How it plays**

- Hold Z and use the arrow keys to carry a particle across the board.

- Link 12 of one colour and they crystallize and vanish. Touching clusters of 5 or more follow in a domino chain, and the remaining particles collapse toward the centre — sometimes setting off the next stage.

- But every swap is work, and work gives off heat: somewhere else on the board, things get messier. Disorder makes the board hotter, and heat makes it mix faster. Big chains are how you cool down.

- Disorder is measured with a coarse-grained Shannon entropy. If it stays at the top for too long, the universe reaches heat death. You can't save it. You can only hold out as long as you can.

A run takes a few minutes. Keyboard only (not for mobile). English and Japanese — press L to switch.

**Behind it**

There's a short design note (PDF, in the downloads) on how each rule was designed from ideas in thermodynamics. The whole game is a single HTML file with no external dependencies; all the visuals and sounds are drawn and synthesized in code.

The code was written with Claude Opus 5.5 (Anthropic) under my direction. The concept, design decisions and play-testing are mine.

**Feedback welcome**

I'd love to hear how long you held out and what your biggest chain was (both are on the results screen) — and anything that felt unclear or unfair. Thanks for playing!