SOUNDER

You are the night operator at a small railway telegraph office.

The dispatcher writes an order on a slip. You key it out on the wire, by hand, one letter at a time, before two trains that cannot see each other arrive at the same piece of single track.

There is no tutorial and nothing to memorise. The code chart is on the screen the whole time — all thirty-six letters and numerals, drawn as the real thing — and the game never asks you to recall any of it. It asks you to read it while a clock runs.

The key is one button

A short press is a dot. A long press is a dash. A gap ends the letter.

That is the entire input scheme, and it is why this game exists on a Game Boy: two face buttons are a terrible keyboard and an excellent telegraph key. Hold it down and the cartridge sounds a tone for exactly as long as you hold it, which is how an operator hears the difference between a dot and a dash.

Take as long as you like over the chart. The office reads your message with the gaps ignored, so hesitating never breaks a word. A message that matches the slip goes down the wire by itself, the moment the last letter lands.

Your typos are simulated, not marked

The line is single track. Seven stations, up to four trains, and a passing loop at every station in between.

• A message the receiving station cannot read is refused, and you send it again. That costs time, and time is the only thing you are short of.
• A message that reads as a different valid order is obeyed. Key 4 where the slip said 1, and the wrong train sits in the siding while the right one runs into the section.

Watch the board at the top of the screen. The engine that pulls up onto the loop is a train that got its order.

Every shift was proved before it shipped

Twelve night shifts, each generated and then simulated twice before it was allowed into the cartridge:

• a perfect operator, sending every order the instant it arrives, clears the shift with no collision, so the shift is winnable;
• a null operator, sending nothing at all, takes a collision every time, so the shift is not safe without you.

A shift that failed either test was thrown away and another generated. The orders were not written by hand either: the generator runs the railway with no orders, finds the first accident, writes the order that prevents it, and runs again until the line is clear.

What it is

• A real 32,768-byte Game Boy cartridge. The download is the .gb file: put it on a flash cart, or run it in any DMG emulator.
• The free browser demo on this page is the same cartridge, running on binjgb, with the first two shifts. No install, no account.
• Twelve shifts, about twenty-five minutes of railway, and a code chart you will stop needing.

Said plainly: this has never been run on physical Game Boy hardware. It is a standard 32 kB ROM-only image with a valid header, verified against the checks the boot ROM itself performs, but we do not claim tests we have not run.

Made with AI, disclosed here and in the store's own fields: the code and the graphics are AI-written. The sound is the Game Boy's own synthesiser driven by register writes, with no samples and no music service.

More Game Boy cartridges from CSAF

WARDLOCK · WITNESS MARK · PROOFMARK · ANATOMIST · ROSE ENGINE

On an Analogue Pocket

The download is a standard Game Boy ROM with no mapper, so on an Analogue Pocket it runs through the openFPGA Game Boy core. We have not run it on Pocket hardware ourselves, and there is no .pocket build in the download.