Logic Masters Deutschland e.V.

This is the successor to my first puzzle, Arrowdynamics, hence the title (can you spot the connection?). I've reformulated the rules slightly since then, and I'm very happy with the result. Enjoy!

Rules:

Normal sudoku rules apply.

Arrows that cover two cells are Double-Digit Summation Arrows. The digits in the two cells covered by such an arrow form a two-digit number when read in the arrow's direction, which is equal to the sum of all cells further along in that arrows direction (in the same row/column/diagonal).

Digits may not repeat in a cage.

Digits separated by an 'X' sum to 10. Not all 'X' are given.

Optional rule: Let me know what you think!