This was my first attempt at a pure killer puzzle, but unfortunately ended up using the X (though I would like to think of the X as a 10 cage that overlaps with the 13 cage).
Rules:
-Normal Sudoku Rules Apply.
-Digits in cages must sum to the number in the top left corner of the cage. Digits may not repeat.
-Cells separated by the X must sum to 10. Not all X's are given.
Links:
F-puzzles
CTC
Solution code: Column 7 followed by Row 4, with no spaces.
Solved by SKORP17, Gryllulus, OhHeyGuysItsMax, jalebc, Kimyee, misko, Bjd, MatB, PippoForte, NB_CN