Logic Masters Deutschland e.V.

Another six-pack! :) So, one large puzzle consisting of six different variants of 6x6 sudokus, which are all linked together by circles.

A digit in a circle acts as a skyscraper clue, indicating the number of visible skyscrapers from that side. Click here for the rules of a skyscraper sudoku.
A circle must contain one digit from 1 to 6 and is an outside clue for both adjacent puzzles.

Normal 6x6 sudoku rules apply to all sudokus, so every row column and region must contain the digits 1 to 6. The different variants in the puzzle:
1) Increasing Sudoku: On every black line the digits are ascending from one end to the other end.
2) Killer Sudoku: rules.
3) Mathrax Sudoku: rules.
4) Clone Sudoku: There are two different shapes in the grid (without rotating). Both shapes are cloned, including the digits it contains. The position of the digits inside each shape is fixed.
5) Arrow Sudoku: rules.
6) Greater than Sudoku: rules.

The puzzle is also available on Penpa.

If you struggle at the start, find a hint here.

Enjoy solving! :)