You lead one of four factions on a world with no dry land. Wall off the sea to make ground, fill it with people, and keep the sea out while the volcanoes throw their waves at your walls. The first seat to hold its bar of people through five of its rounds wins.

To begin, on the start page click a colour for each seat: once for a human, twice for a computer, a third time to leave it out. The order you pick is the order of play. Then press Start Game.

A realm on the globe: the polders (walled hexes), the mountains (the five-sided tiles) and the open sea.

1Build

You have one action a turn. Pick Polder in the palette (bottom right) and click a sea tile beside a mountain: walls rise, the sea is pumped out, and your first 50k settlers arrive. Every later polder joins your land. It is paid in lava from a mountain your land touches, and manned by your people: 1k for each of its walls.

Hover anything in the palette to see what it costs and what it does. Press End Turn when you are done; Restart Turn takes the turn back, once.

The ghost shows what a click will build; the card beside it, what it costs.

2Grow

People move into new ground and grow every round, up to what each polder can house and feed. Housing needs power, and a mountain’s lava is its power: every build spends some, so the grid dims until the mountain refills. Keep each polder at 50% power or more, or it goes dark.

A Township raises the housing on its polder and the ring around it. Hover a polder for its card.

The polder’s card: how it stands, its people, housing, power, food and walls.

3Repair

Waves damage walls: a damaged wall wears a red hem at its foot. A lit, lived-in polder mends its walls every round; a dark one lets them weaken. Repair makes a wall whole at once, with your action or with thalassyrium (⬢) once it is spent.

A broken wall floods the polder and the land joined to it. Rebuild it with your next action, or it goes back to the sea.

A flooded polder: the number counts its rounds left.

4Survive

The core pressure (top left) rises every round. Mountains wake (a yellow disc) and erupt: the surge runs across the sea and the quake breaks the walls of every polder touching the mountain. Right-click a mountain for its forecast: walls in red would break.

Every polder anyone builds raises the sea for everyone, so walls weaken as the world fills. Forts hold twice the sea a wall does, and an Emergency’s crews patch a breach in time, given a deep polder to hold the water.

A forecast: the wave’s peak on each sea tile, the walls it would break in red.

That is the whole of it. Thalassyrium, institutes and their techs, allies and rivals, medals and culture are in the Reference, with every rule; The world tells the story. Control, at the bottom of the screen, says everything that happens as it happens.

Polderv0.22 beta

Diplomacy