Flooded Caves

Each of these logic puzzles is a variant of the Cave logic puzzle format. Upon solving each puzzle, the discoverer quote identifies a specific dead end in the cave, which gives a number from the grid at the bottom. See the Appendix below for solutions to each logic puzzle.

Many of the treasures have specific descriptions that can be identified, and the explorers all have some odd quirks that may help set them apart. These, along with "God" and "mother" in the flavortext, lead us to discover that this puzzle is referencing the popular roguelike video game The Binding of Isaac. Each of the treasures is an item from the game, and each of the explorers is a character. The treasures are given in alphabetical order, so we can reorder by the characters' in-game order (source), and index with the numbers from the logic puzzles:

The next instruction is to APPLY SPINDOWN DICE. Spindown Dice is an item from the game which transforms other items by decrementing their ID numbers by one. This gives us a new set of items to index into, using the same numbers:

Finally, we must FIND THE SECRET ROOM. Secret rooms in The Binding of Isaac are rooms that don't appear on the map, and typically appear bordering 3-4 other rooms. In fact, each of the logic puzzles' solutions contains a unique shaded cell that borders 3 unshaded cells. Using these secret room locations with the grid at the bottom, we get a new set of numbers, which we use to index into the spun-down items once more:

The answer to this puzzle is GOLD TOUCH.

Authors' Notes

• This puzzle was always a Binding of Isaac puzzle, but went through many changes from its initial idea! We originally considered a text-adventure layout with bombs you could use to enter the secret rooms. There was also a final extract concept that used Pokémon. The logic puzzle format ended up winning out due to ease of construction, more variety in rulesets, and thematic aptness with the idea of exploring a cave.
• The puzzle's title is also a reference to the Flooded Caves level in Isaac.

Appendix: Logic Puzzle Solutions

Yellow cells are treasure rooms (unshaded). Purple cells are secret rooms (shaded). We also include notes about the break-ins for some of the harder variants.

1 (numbers can be shaded)

• This puzzle hinges around the 11 clue. If the 11 clue were to be unshaded, it would take at most 4 cells horizontally and at most 6 cells vertically due to the 4 clues in its row or column. After getting that the 11 is shaded, being connected to the outside means that it can only see in 3 out of the 4 directions, which barely leaves room to see 11 cells, not using itself.

2 (even columns)

3 (chess)

• This puzzle solves very differently from a cave. The B and N clues are the most constraining at the start. There are only two possible ways the B clues can go from the outset, while the N clues can mark many shaded cells once three cave cells are attacked.

4 (primes/squares/cubes)

• The only cube clue possible in a grid of this size is 8, and the possible square clues are 4 and 9.

5 (minesweeper indicating cave cells)

• This puzzle solves somewhat similarly to a Tapa, a different puzzle genre with similar clues. Connectivity is the key here: for example, the cave connecting through the corridor between the 2 and 3 on the left would take too many cave cells for the 2 clue.

6 (even/odd)

• With the alternating even-odd zigzags, the length of the segment in each row and column must also alternate (in the portions connected to E/Os). After deducing that the 10 clue must see at least 6 cells up, if the 5 sees 4 cells down and none to the right, then we get a vertical column of 5 next to a vertical column of 7, contradicting the even-odd constraint. The same logic rules out 5 seeing 2 down and 2 right or 3 down and 1 right when applied to the sections in column 1 and 3, whose lengths must have the same parity.

7 (portals)

8 (products)

9 (plus/minus one)

10 (69)

• This puzzle can be started by using standard cave deductions, like the fact that a 9 in the same row or column as a 6 has to extend at least 3 cells in the perpendicular direction. This ruleset turns out to be quite constrained and still has a unique solution even when many of the clues are removed, but is much more difficult to solve logically.

11 (shaded/unshaded circles)

• The 7s and 8s on the border are forced to be Cave clues, and the given shaded circle forces the 7s to connect vertically. The break-in here is to consider the 8 in row 3, column 3: if it is unshaded, it can’t connect horizontally to the 7 or 4 in its row, so it uses at most 4 cells horizontally. This would force it to use at least 5 cells vertically, contradicting the 3 clue.

12 (rotational symmetry)

(13 crossword)

• The main constraint in this puzzle is that every run of unshaded cells (except ones distance one or two from the bottom or right side) must have length at least 3. This heavily constrains unshaded cell placement along the top and left edge, and lets us deduce that the 5 can see 2 more cells in each direction.

14 (letter variables)

• The first thing to notice in this puzzle is the rectangle of EAFF on rows 2 and 3 columns 5 and 8. If these clues could see each other, we would need E + F = A + F, which would make two of the variables equal. This gives us that both cells to the left of the Fs are shaded. Additionally, all letters have at least one occurrence that is forced to see 3 cells, except for G which is only adjacent to a single A, so G must equal 2.

15 (pentominoes)

16 (minesweeper indicating non-cave cells)

17 (no 2x2)