PERIGEE

A settlement stands on a shelving coast. It wants water in some places and never in others, and it will not listen to you.

You are not its god of harvests, only of tides. You set the moon's orbit, and everything the sea does follows from where the moon is. There is no direct power anywhere in this game — no building, no digging, no blessing, no smiting. One lever, and a coast that answers it.

Free, plays in the browser, about fifteen minutes for a full run of ten seasons. Your progress is saved after every season.

The tide is real physics, and that is the whole design

Tide-raising force falls off as the cube of distance. So bringing the moon close does not raise the tide a little — it raises it enormously. Across the legal orbital range that is 0.13 m of amplitude at apogee against 1.47 m at perigee, out of one equation. Perigee is not a tuned power-up; it is an inverse cube doing the work.

Three consequences you will feel in the first minute:

• The moon has weight. It answers slowly. A dive to perigee has to be started hours before the hour that needs it — and you will still be low when the water reaches the fields.
• High water travels along the shore. It does not arrive everywhere at once, so the far end of the coast floods later than the near end. Where a structure stands decides which hour is its hour.
• The coast remembers. Every tide cuts at the waterline and lays the spoil seaward. At the end of a season the ground has moved — so the sills move with it, and last season's safe orbit is not this season's.

Four things that want four different seas

• The tide mill wants water just over its sill, and moving. A drowned wheel stops as surely as a dry one.
• The salt farm wants never to be flooded. Salt in a field is not gradual.
• The cistern wants one rare high tide over its lip. It then holds for days.
• The dock wants depth over the bar, and does not care how much.

The tide that turns the mill drowns the low field. The cistern can only be filled by a tide that would ruin both. You cannot satisfy them at once, so you sequence them — and salt in the fields throttles everything the settlement produces, which is what stops "dive and stay there" from being the answer.

Everything you buy is the sky

Nothing in the upgrade tree improves the settlement. The settlement is not yours.

TIDE TABLE — a forecast, so a dive can be started on purpose instead of in hope. SLIP — the moon answers faster. MASS — every tide grows, including the one that takes the field. ECCENTRICITY — the orbit breathes across the month on its own. APSIDAL CONTROL — you choose when in the month perigee falls. THE SECOND MOON — two tidal waves add: when they agree the sea rises higher than either could lift it, and when they argue it barely moves. RESONANCE — lock them to a 3:2 ratio so the pattern repeats and can be planned around.

If a season goes badly

The settlement loses a point of standing. At zero it stops looking up — and you begin that same season again, from the checkpoint written when it opened, with the coast, the settlement and every upgrade kept. There is no full restart in this game except the one you ask for by name.

Controls

W / S or the arrow keys set the orbit · mouse wheel over the map · drag up or down on the map · SPACE pauses · F runs faster · M mutes.

Honest notes

• There is no level file and no heightmap image. The coast is generated at run time from a seed and then edited by the sea; the nine material surfaces, the twelve structure sprites and both moons are drawn by our own generator from a palette authored for this game.
• Nothing is downloaded. No font file, no library, no framework — the typeface is whichever of Iowan Old Style, Palatino, Georgia or your system serif you already have.
• AI disclosure: the code is AI-written and the store cover is AI-generated. The sound and music are not — they are procedurally synthesised from oscillators and noise by our own tool, which itch is explicit is not generative AI. CREDITS.txt in the build lists every file that ships and where it came from.

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More from Core Systems Asset Factory: csaf.itch.io — free browser games, and tools and asset packs for developers.