Logic Masters Deutschland e.V.

Click the image to play. Note that support for puzzles like this in SudokuPad is still under development, so it may not work properly in all browsers or platforms. Zooming can be enabled (if your platform supports it) by going to the bottom of the settings and switching "Test Large Puzzle UI" to "On".

This was my entry for Turn 4 in The Skunkworks League, for which the prompt was to create a puzzle with a four-cell solving space. My original submission only allowed digits to be entered into the four cells outlined in red, because I felt like that was more within the spirit of the prompt, but for this version I've enabled notations throughout the puzzle. (If you don't like this giant puzzle trend, sorry! This will (probably) be my last for a while.)

Rules
This is a set of nine 9x9 puzzles that, taken collectively, has multiple solutions. Fortunately, your job is simply to place digits in the four cells outlined in red in the central grid.

Normal sudoku rules apply within each 9x9 grid, and all clues are standard (as defined below). However, across the entire set, exactly one instance of each clue is "wrogn". A clue is wrogn if it is not 100% correct (e.g. a whisper is wrogn if *any* two adjacent digits differ by less than 5).

Cages: the sum of the digits inside each cage is equal to the small number in the top left corner (if given), and digits cannot repeat within a cage.
Arrows: the sum of the digits along an arrow is equal to the digit in the connected circle, and these digits can repeat if allowed by other rules.
Thermometers: digits on thermometers increase from the bulb.
Region sum lines: box borders divide each blue line into segments with the same sum.
German whispers: along green lines, digits differ from their neighbors by at least 5.
Renban lines: purple lines contain a non-repeating set of consecutive digits in any order.
Palindromes: gray lines (without bulbs) are palindromes, which contain the same sequence of digits in either direction.
Digits in cells separated by a white dot are consecutive.

For more of my puzzles, check out Artisanal Sudoku