Resonance Cave – a cave logic puzzle with gravity

How it works

The cave is a grid of cells seen from the side. Solid rock walls cannot be changed. Earth can be removed by walking into it or by digging it away next to you. Tunnels are free cells. Lying around the cave are loose rocks, crystals and an exit. Your figure moves exactly one cell up, down, left or right per move; it does not fall itself, but rocks do.

• Crystals: Stepping onto a cell with a crystal collects it at once. Only when every crystal of the level has been collected does the exit light up, and the level is done as soon as you step onto it.
• Rocks: A loose rock falls as soon as there is neither wall nor earth nor another rock beneath it. Your figure does not stop it: if a rock lands on you, the attempt is lost. You can push a rock only sideways, by one cell, and only if the target cell is free. Chains of several rocks cannot be pushed.
• Digging without moving: Walking into earth digs it away and moves you in. With the G key and a direction (on a phone with ⛏ below the board) you instead remove one earth cell next to you without moving; afterwards digging is off again. That lets you drop a rock from a safe distance instead of walking underneath it.
• Resonance rocks: Two rocks with the same colour and rune are coupled. Push one, and the other moves in the same direction in the same move - even if it lies somewhere else entirely. If either of them cannot move because a wall, earth or a rock is in the way, neither moves, and the obstacle is briefly highlighted. If a resonance rock falls afterwards, it falls alone; the partner stays where it is.
• Moves and restart: Every successful action costs one move, no matter how many rocks fall afterwards. An invalid move costs nothing. You cannot take a move back: if you get stuck or end up under a rock, “Restart” or “Try again” begins the level from the start. There is no clock and no time pressure.

The eighteen levels build on each other: first you walk and dig, then you push a rock, then you learn safe digging, then an avoidable dead end, and from the fifth level on the coupled rocks arrive. Levels 13 to 18 go deeper: preparation at the other end of the cave, a push that has to stop halfway, two conditions at once, two partners that take turns as the grip in both directions, a consequence that only shows moves later, and a small finale. From the sixth level on the text above the board only states the goal; if you are stuck, you can reveal hints in three stages, from a guiding question to the approach. Finishing a level unlocks the next; for every level the game remembers your best number of moves. Whether that progress stays only for this session or persists on the device follows the “Save progress” setting; see the privacy statement for details.

Tips & techniques

• Look at what would fall first. Before you step into an earth cell, look up: if a rock lies there, it loses its support the moment you enter and falls right onto you. Dig such cells away from the side.
• A shaft swallows a rock. A rock that drops into a deep shaft is out of the way. A rock that drops into a shallow shaft blocks it. Count how far down it goes before you dig.
• A rock in front of you stays in front of you. In a corridor you can only push a rock ahead of you. The corridor only opens once the rock escapes into a niche or a shaft - or once you let it drop from below.
• Think of the partner. Before every push of a resonance rock, check where its partner would go. If there is earth, dig it free first. If there is a drop behind it, the partner falls - sometimes that is exactly the way.
• Order before path. A crystal behind a rock is lost if the rock ends up lying on it with nowhere to go. Collect what lies behind a rock before you move it - or move it the other way.
• A restart is not a flaw. The best score counts the moves of the run that finally solves the level. A failed attempt costs nothing; it only shows you which move came too early.

Frequently asked questions

What is a resonance rock?

A loose rock with a partner. Both carry the same colour and the same rune. Push one of them, and the other moves in the same direction in the same move, however far away it lies. Both move, or neither: if the target of either one is blocked, nothing happens at all.

Why does the figure die when I walk into earth?

Because the earth under a rock is exactly what holds it. Step into it and it is gone, and the rock falls onto the cell you are standing on. Dig such cells from the side with G and a direction (or ⛏): the figure stays put, and the rock falls next to it.

Is there a time limit?

No. Nothing moves until you make a move, and you can think as long as you like before each one. The game asks for the right move, not the quick hand.

What about a crystal with a rock on top of it?

The crystal stays and remains visible as a small mark. Push the rock away or let it fall further, and you can collect the crystal. If the rock is stuck in a corner, only a restart remains.

Is my progress saved?

Unlocked levels and best scores stay for this session. If you have turned on “Save progress” in the settings, they also stay on this device afterwards. You do not need an account, and there is no leaderboard.

Is this a finished game?

No, a prototype with eighteen levels. It is meant to show whether the rule with the coupled rocks is understandable and carries good puzzles. Rules and levels may still change; a running attempt is then reset, finished levels stay.