DrX is wrong. I've already found several solutions that aren't the right one and that was after several educated guesses. The bottom portion contains the word FIST! The rest is symmetrical. I think it's solvable after r13c10 But if not, the other ambiguities are r14c8 r15c4,6,7 r16c5,8,9.
Maybe this have been updated since last comment.
Thnaks.