Falling Tiles

The chamber floor is safe for about half a minute. After that the quicksand is over the tiles, and the only ground left is stone: what has fallen from the ceiling, what you have raised yourself, and what nobody has blasted out from under you yet. A round is 75 seconds of building upward faster than the sand climbs.

The sand's timetable

For the first five seconds the sand sits well below the floor. It reaches the tiles about 30 seconds in, and from then on the floor will swallow you. After that it climbs faster, roughly 6 cm a second. A one-high stone goes under at about 45 seconds, a two-high stack at about a minute, and by the buzzer the surface is close to 2.8 m, so you need to be three stones up to see the end. The HUD shows the sand's height throughout.

Sand within 10 cm of your feet counts as sinking. It drags at you, and after under three seconds in it, or once you are 75 cm under, you are out.

What falls

Each monolith marks its landing spot with a glowing rune and takes 1.5 seconds to come down. Caught under one at floor level, you are thrown clear and stunned.

There are five shapes: a 1 by 1 cube, a pillar three cells long, a 2 by 2 altar, a step whose lower half you can walk straight up, and a two-high arch you can run under.

The three keys

• Q, Shove (0.8 s). Throws every rival within about 1.8 m the way you are facing, wherever they stand around you, and stuns them briefly. With nobody in reach it pushes the cube in front of you one cell along, if that cell is empty. Only cubes move.
• E, Sand Burst (4 s). Smashes the block that glows gold on your screen: the one in front of you, or the one under your feet if nothing is ahead. Anything stacked on it drops down.
• R, Raise Block (5 s). A cube appears under you and lifts you a metre, and your sinking count starts again. At the height limit it lays the cube in front of you instead, level with your feet, as a bridge.

Cubes come in four colours. Three of one colour touching on the same level, diagonals included, crumble together.

Staying up

• Be on stone by 30 seconds, two high by 45 and three high by the minute.
• Once the floor is gone, keep R ready when you can. It is the surest way out of the sand.
• An arch is two tiers in one stone. Climb onto it from a one-high block beside it.
• Late on, Sand Burst the top stone of a rival's tower. They fall to whatever is below, often straight into the sand.
• Shove follows your facing, not where the rival stands. Turn so that forward is off the edge of their stack first.
• Watch the colours under your feet. A cube landing or raised beside two of its own colour takes your floor with it; shove one into place to do the same to a rival.

Bigger chambers

The chamber is a 10 m square with two or three players, 12 m with four or five, 14 m up to eight and 16 m from nine. Stone falls faster as it grows: every 1.5 seconds, then every 1.2, then two at a time every 0.8 seconds from six players. The sand keeps the same timetable at every size.

If more than one of you lasts

When two or more are still above the sand at the buzzer, the order between you goes to whoever has worked the most stone: 150 for each block burst and 50 for each cube raised. Everyone who sank is placed by how long they lasted.