Insane puzzle: mate in 18

Yo, somewhere in this game that I was playing, the computer showed mate in 18, I can't find the position anymore. But I am intrested in mate in 18, just like you, because you clicked on this.
So here is the game:

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "1-0"]
[Link "https://www.chess.com/analysis/collection/tegen-papa-23TCoyAB8/2GCRs39Kyx/games?move=88"]

1. g4 b5 $9 2. Bg2 $6 c6 $6 3. Nc3 $6 g6 $2 4. d3 $6 h5 $6 5. h3 $6 Nf6 $2 6. g5 Nh7 7.
Qd2 $6 b4 8. Ne4 $6 a5 (8... c5 $2) 9. Qf4 f5 10. gxf6 exf6 (10... Na6 11. f7#) 11.
Nf3 Qe7 12. Nd6+ Kd8 13. Nc4 g5 14. Qf5 h4 15. Be3 Ra6 16. Bb6+ $1 Rxb6 17. Nxb6
Rg8 18. Nd4 Qd6 19. Qxh7 Rg7 20. Qh6 $2 Qxd4 21. Qh8 Ke8 $2 22. Nxc8 Qxb2 $6 23. Nd6+
Ke7 24. Nc8+ $6 Ke8 $6 25. O-O $6 Qxc2 $6 26. Qh5+ Rf7 27. Nd6+ $4 Bxd6 $1 28. Qg6
Qxe2 $4 29. Rfe1 $1 Qe5 30. Qg8+ Bf8 31. Rxe5+ fxe5 32. Qg6 Be7 33. Rd1 (33. Re1)
33... d6 34. d4 c5 (34... Bf6) (34... exd4) 35. dxe5 Nd7 36. Bc6 Kd8 37. Qxf7
(37. exd6 Rf6 38. dxe7+ Kc7 39. e8=Q Nf8 {+M3} (39... Rxc6)) 37... Nxe5 38. Qe8+
Kc7 39. Kg2 (39. Bb5) 39... c4 $6 40. Qxe7+ Kxc6 41. Qxd6+ Kb5 (41... Kb7 {+M3}
42. Qe7+ (42. Rd5) (42. Qxe5) 42... Kc6 (42... Kb6 43. Qd6+) (42... Ka6 43. Qxe5
g4 44. Rd6+ Kb7 45. Qe7+ Kc8 46. Rd8#) (42... Kc8) 43. Qd6+) 42. Qxe5+ (42. Qe7)
42... Ka4 43. Qe8+ (43. Rd5 $3 Ka3 (43... c3 44. Rxa5# $9) (43... b3 44. Rxa5+ Kb4
45. a3# $9) (43... g4 44. Rxa5# $9) 44. Rxa5# $9) 43... Ka3 44. Rd2 b3 45. Qe7+ Ka4
46. axb3+ cxb3 47. Rd4+ Kb5 48. Qe5+ Kc6 49. Rd6+ Kc7 50. Qe7+ Kc8 51. Rd8# (51.
Rd8# {+M5}) 1-0

I think it was in the middle game, around 20-30 I think, maybe a little later

Also sorry if the bad playing annoys you