PYRAMID

The dead come up the causeway in procession — jackal-headed, bandaged, patient — and the only thing between them and the seal is what you can raise out of the desert.

The pyramid is both your health bar and your wallet. Every obelisk, brazier and snare you build is paid for in stone carved off the monument itself, so each tower you raise makes the thing you are defending shorter. Kill the dead and you earn the stone back; let one reach the seal and it shatters a course. Spend too much and you tear down your own monument. Spend too little and the procession walks in.

How to play

• Click a plinth to raise the tower you have selected. Click a standing tower to raise it higher.
• SEND WAVE starts the next of eight waves. Build between them — that is the only time you have.
• OBELISK — 4 stone. A blade of sunfire: one target, long reach.
• BRAZIER — 6 stone. Fire that splashes a whole group.
• SNARE — 3 stone. No damage at all; it ties everything in its ring to half speed.

Clear all eight waves with the pyramid still standing. The last of them is the Sand Colossus, and it is the size of a house.

You are the Keeper. You have no body — only the hand that places stone.

Behind it

Ten build plinths along a winding causeway, four kinds of the dead, and a night that ends in either dawn or an open seal. Built in Zero: the causeway the dead walk is the same curve the road mesh is drawn from, and the pyramid's courses are the stone count — the monument visibly shortens as you spend it and grows back as you earn it.