Three worlds

How a run goes

A run is a map of ten layers. The whole map comes from the run’s seed and is in view from the start. Layer 1 is a single board; layers 2 to 4 and 6 to 8 each offer two or three stops; layer 9 offers a place to rest and an event, and you may take either; layers 5 and 10 are the bosses. Every route has between five and nine boards, the two bosses included.

• Board: choose one of three relics when you win it.
• Hard board: 2 fewer clues, then choose one of four relics and strengthen one you hold.
• Rest: get 2 lives back (1 from Depth 5 on), or strengthen a relic.
• Event: one of eight, all laid out in the open: a gnome who trades a life for one of five relics, a chest where you leave one relic and take two, a key that turns a relic into another of its set, and five more. There is no money in them.

The Cellar

Classic sudoku, from 6×6 up to 9×9.

Layers 1 to 5 are 6×6, layers 6 to 10 are 9×9. This is where you learn the two ways to move forward without guessing: the only digit that fits a square, and the only square a digit fits.

Bosses

Layer 5, the Snail: one digit may not stand in any corner of the board, and one hatched box stays shut until two other boxes are full. Layer 10, the Mushroom: two digits may not stand in a corner, and the middle row and column are shut: a square there opens when the rest of its row or column is full. The rule is written on screen and shown on the board.

The 14 relics of this world

• Candle Stub. Squares with only one digit left glow softly.
• Moss. Every 3 finished rows, columns or boxes on a board give one life back.
• Root. Every board starts with all possible digits written as notes.
• Cobweb. After a mistake you see which digits do fit in that square.
• Dripstone. Pick a filled square: every empty square where its digit can still go is outlined.
• Snail Slime. Making the same wrong move in the same square again costs nothing.
• Rootstock. Every board starts with one extra given digit.
• Dew. A board finished without a mistake gives one life back.
• Bat. Notes that can no longer be right disappear by themselves.
• Boot. The first mistake on each boss board costs nothing.
• Sprout Fungus. A row, column or box with one empty square fills in by itself.
• Glow Fungus. The lantern also tells you which digit goes in the square it points at.
• Creeping Root. Boss boards start with two extra given digits.
• Thread. Every 8 correct moves in a row give one life back.

The Library

Killer sudoku: cages with a sum.

A dotted cage must add up to the number in its corner, and a digit may not repeat inside it. The cages carry the puzzle, so there are far fewer given digits. Opens when you finish the Cellar.

Bosses

Layer 5, the Squid: one cage is hidden. It appears after a mistake, or when half the other cages are full. Layer 10, the Librarian: two cages are hidden in the same way, and a mistake wipes your notes in that box. A cage is only ever hidden when the board can be solved without it, so you never have to guess what it was.

The 14 relics of this world

• Bookmark. Every cage shows how much of its sum is still missing, next to the sum.
• Sum List. Pick an empty square in a cage to see the digit combinations that still make its sum.
• Margin. A cage with one empty square fills in by itself.
• Register. Cages that can only be finished one way are outlined.
• Duster. Notes that the cage sum rules out disappear by themselves.
• Footnote. After a mistake in a cage you see the combinations of that cage.
• Wax Seal. Every board starts with its smallest cage already filled in.
• Black Light. Hidden cages are visible from the start.
• Stamp. Every 3 finished cages on a board give one life back.
• Catalogue. The first mistake in each cage costs nothing.
• Marginalia. Notes start in every cage square, with only the digits the cage sum allows.
• Slide Rule. Digits the cage sum rules out are greyed out on the keypad.
• Librarian. Boss boards start with their two smallest cages filled in.
• Ribbon. The first cage you finish on each board gives one life back.

The Attic

Thermometers and diagonals.

Digits on a thermometer must rise from the round bulb to the tip. On a diagonal board, both long diagonals hold every digit once, like a row would. Opens when you finish the Library.

Bosses

Layer 5, the Clockwork Mouse: both diagonals hold every digit once, and the hatched diagonal stays shut until the other is full. Layer 10, the Star Owl: diagonals and thermometers on a 9×9 board, and in every box the hatched square stays shut until the rest of that box is full.

The 14 relics of this world

• Pendulum. Pick an empty square on a thermometer to see the lowest and highest digit it can hold.
• Clockwork. Every thermometer you finish gives one life back.
• Suitcase Key. A thermometer with one empty square fills in by itself.
• Mercury. Notes start in every thermometer square, with only the digits that still fit.
• Brass Bulb. Notes in thermometer squares that can no longer be right disappear by themselves.
• Thermostat. The first mistake on each thermometer costs nothing.
• Moonlight. Thermometer squares with only one digit left glow softly.
• Star Chart. Pick a square on a diagonal to see which digits that diagonal still misses.
• Mirror. On boards with diagonals, each diagonal starts with one extra given digit.
• Weathervane. The first mistake on a diagonal on each board costs nothing.
• Sundial. Every diagonal you finish gives one life back.
• Attic Lamp. The lantern looks at the thermometers first.
• Suitcase Lock. Every thermometer starts with its bulb already filled in.
• Sky Map. You may carry one more life than usual.

Shared relics

These 16 can appear in every world.

• Black Candle. A flawless board gives 2 lives back. Price: a mistake costs 2 lives.
• Cracked Lens. Every board starts with full notes that keep themselves tidy. Price: your maximum is 2 lives lower.
• Heavy Pack. Take 2 more relics from this offer right now. Price: every later offer is one smaller.
• Silent Bell. Every finished board gives a life back. Price: the owl and the lantern no longer work.
• Ink Blot. Boss boards start with 3 extra clues. Price: every other board has 2 fewer.
• False Bottom. Every set bonus starts one relic earlier. Price: your maximum is 1 life lower.
• Pencil. Placing a digit clears it from the notes of every square it touches.
• Owl. Once per board, the owl fills in the square you pick.
• Second Chance. The first mistake on each board costs nothing.
• Lantern. Once per board, the lantern points at the easiest square.
• Heart. One extra life, right now.
• Compass. The digit buttons show how many of each digit are still missing.
• Bandage. Beating a boss gives one life back.
• Feather. The owl and the lantern work one more time per board.
• Magnifier. Picking an empty square shows which digits still fit there.
• Anchor. Once per run, a fatal mistake leaves you with one life.

Six sets

Every relic belongs to a set. Two relics of a set give its small bonus, three give its large one. The number after each name is how many relics belong to the set.

• Life (11). Two: One more life than usual. Three: Every finished board gives a life back.
• Shield (8). Two: The first mistake on a hard board or a boss costs nothing. Three: The first mistake on every board costs nothing.
• Light (9). Two: The lantern works once per board, even without the Lantern relic. Three: The lantern also names the digit.
• Notes (8). Two: Notes that can no longer be right disappear on their own. Three: Every board starts with full notes.
• Gift (11). Two: Every board starts with one extra clue. Three: Boss boards start with three more clues.
• Lore (11). Two: Digits that do not fit the chosen square are greyed out. Three: Squares with only one possibility light up.

Some relics can be strengthened at a rest or after a hard board. A few carry a price: a strong gain and a real cost, both written on the card.

Ten Depths

Every world can be played on ten Depths. Winning a Depth opens the next. Each Depth keeps the rules of the ones before it. A board earns a star for finishing it, one for no mistakes and one for no fill-in help.

1. Depth 1. Gentle: 4 lives and 2 extra clues on every board.
2. Depth 2. The game as it is meant: 3 lives.
3. Depth 3. Added: 9x9 boards have 2 fewer clues.
4. Depth 4. Added: ordinary 9x9 boards ask for a harder technique.
5. Depth 5. Added: a rest gives 1 life back instead of 2.
6. Depth 6. Added: every offer after a board is one relic smaller.
7. Depth 7. Added: boss boards have 2 fewer clues.
8. Depth 8. Added: you can carry one life less.
9. Depth 9. Added: from layer 3 on, every board asks for the hardest technique.
10. Depth 10. Added: you start with 2 lives.

Also in the game

• Daily run: one per world per day, the same seed for everyone, with a streak of days in a row.
• Endless: for each world you have finished, go as deep as you can.
• Seeds and results: a run is fully decided by its seed, so you can share one and play the same run as a friend. After a run you can copy your result, with your route and seed, as text.
• Lessons: six short, optional ones with Nikkel the gnome: the only digit that fits a square, the only square a digit fits, cages, thermometers, diagonals and pairs.