This idea is partly inspired by two puzzles: "Archer Towers" by Angelo and "Nadir" by Barrels. If you're feeling stuck, check out the walkthrough of the solution below. Props to anyone who knows the title's reference ;-) Comments and ratings are much appreciated, and please be sure to check out my other puzzles here.
Normal sudoku rules apply.
Thermometers: Along thermometers, digits increase from the bulb to the end.
Peaks: A cell with arrows pointing outward is a peak, which is greater than its orthogonally adjacent cells. A peak sees all digits less than it to the north, south, east, and west, except for those hidden by digits larger than the peak. A peak of value x sees a total of x digits.
Valleys: A cell with arrows pointing inward is a valley, which is less than its orthogonally adjacent cells. A valley sees all digits greater than it to the north, south, east, and west, except for those hidden behind larger digits. A valley of value x sees a total of x digits.
Suppose a row contains the digits 5 1 2 7 6 9 4 8 3.
If 7 is a peak, it sees all three cells to the west (2, 1, and 5) and one cell to the east (6). It doesn't see 8 or 9 because they are larger than 7, and the 9 hides the 4 and the 3.
If 1 is a valley, it sees one cell to the west (5) and three cells to the east (2, 7, and 9). The 7 hides the 6 and the 9 hides the 4, 8, and 3.
Lösungscode: Enter columns 2 and 3 (18 digits, no spaces)