Including the hostile ones.

The free edition is free, and it is one assignment at a time: this week’s metro under this week’s mandate, in 2025, for five years of game time, with the entire simulation in it — the full demand model, the operating budget, the events, the strike, the land use and the whole progression ladder. A new pair arrives every Monday, and a game you have started keeps going after the week turns. It needs a sign-in.

The full edition is $20, once: all 54 metros, eight decades, every mandate and every mode, no clock, and it installs as an app that plays offline. The source is MIT licensed and on disk either way.

Because the model is the entire claim. A demo that cripples the simulation would be advertising something the buyer does not receive. A demo that hands over one complete city proves the claim and makes the case for the other fifty-three metros and the other seven decades — which is what the full edition actually is.

Locked cities and decades are shown, named and labelled, never hidden. A paywall that pretends the content does not exist is both a worse experience and a worse pitch.

The full edition does not. It installs as an app, keeps the metros you have opened on the device, and plays with no connection; a signed-in device stays trusted for thirty days at a time and renews whenever it connects.

The free edition does: this week’s assignment is resolved against your account, so it needs a sign-in and a connection. Either way the engine runs in a worker in your browser, your saves stay on your device, and there is no telemetry.

Yes — with Claude, stated here and in the repository's README unprompted. The research behind this project found that concealing AI assistance, not using it, is what cost a comparable title its audience: undisclosed AI use appears in roughly 15% of that game's Steam reviews and in its second most-upvoted one.

The mitigation is not a promise, it is the artefact. The engine is open source, the model is specified in full, every calibration constant carries a comment citing its source, and the whole thing is deterministic — so none of it has to be taken on trust.

Because the data pipeline reads US federal datasets: Census PL94-171, ACS, LEHD LODES and FHWA HPMS. Those are what make the observed commute matrix possible, and the observed commute matrix is the difference between this and a distance-based gravity model.

Other countries have their own equivalents and they are not interchangeable. Non-US metros are planned as a real piece of work, not as a setting.

A game. It is a strategic-level model, not a piece of practice software: it will tell you correctly that a line relieves a corridor and it will not tell you what happens at an intersection. It does not simulate streets, it does not do signal timing, and it will not produce anything you should put in front of a board.

What it will do is be wrong in the ways real models are wrong, and show you where.

The walkthrough is six steps and teaches five verbs: read, site, build, run, and let the clock go. After that, Field Notes is a pull surface you open when you want to get better, and every note in it carries the file and function in the engine that produces the behaviour.

It is still a deep game. The claim is not that it is easy, it is that you will not have to open a forum in another tab to find out what a button does.

Four things a person who owns them can check in about a minute. Interurban seeds work trips from observed LEHD LODES origin-destination pairs and predicts only the change the network causes, rather than synthesising the whole matrix from a distance-based gravity model. It runs eight decades, each moving nine independent levers, rather than one present day. It has seven modes including bus, BRT and ferry, rather than being subway-first. And every calibration constant sits next to a comment naming where it came from.

“Real data” is not the differentiator. It is a floor, and several of these games clear it. What is on the page for checking is the method.

That is the intention and it is one of the specific failures this project is designed around — “updates break existing saves” is one of the most-upvoted complaints in the competitive research. The save format is versioned. It has not yet been through a real migration in public, so this is a design commitment rather than a track record, and it is described that way on purpose.

Yes. Features & mechanics walks through the four steps, the operating budget, the events, the land use and the career ladder, and the source is MIT licensed: every coefficient lives in src/engine/constants.ts beside a comment naming where it came from, and the seven things the model cannot do are listed with the code.

It is written as documentation rather than as marketing.