It is clear that the Queen has to leave the long diagonal. What I like: the intuitive 37-42 is only draw. The other 3 counter-intuitive moves on the short diagonal win, if Queen goes to 42 in the next move, creating Zugzwang.
52. .. 12-18 is very inferior move.
Black has solid material advantage, and there is NO rational reason to go for king endgame!
Please, keep in mind that if you have significant positional or material advantage, the best means for eliminating draws and complicating things is to play for OPPOSITION or ZUGZWANG. You need to know king endgames very well in order to understand if your opponent have chances to escape a loss.
Therefore, 52. .. 17-22 53. 34-30 (nothing better) 23-28 54. 30x19 14x23! and white must surrender.
59. .. 48-37? indicates that a player has a little experience in handling kings.
59. .. 48-25, and white can't exploit majority capturing by 60. 19-14: black has two valid capturing choices. Both 60. .. 25x18 (or down to further squares on same diagonal) or 60. .. 8x30 are winning.
Thank you kalnap!