why isn't this move brilliant

[Event "Illion1961xy vs Lichessun"] [Site "Chess.com"] [Date "2025-07-31"] [White "Illion1961xy"] [Black "Lichessun"] [Result "0-1"] [WhiteElo "1125"] [BlackElo "1131"] [TimeControl "600"] 1. b3 d5 2. Bb2 c5 3. e3 Nc6 4. g3 e5 5. Bg2 Nf6 6. Ne2 Be7 7. c3 O-O 8. d4 e4 9. O-O Be6 10. Nd2 Qd7 11. c4 cxd4 12. Nxd4 Nxd4 13. Bxd4 Bh3 14. Bxf6 Bxf6 15. Rc1 Bxg2 16. Kxg2 dxc4 (16... Rad8) (16... Rfd8 17. cxd5 Qxd5 18. Nxe4) 17. Nxc4 Qxd1 18. Rcxd1 Rad8 19. Rxd8 Rxd8 20. h4 b6 21. Kh3 Kf8 22. Kg4 Rd5 23. Kf4 b5 24. Na3 Bb2 25. Nc2 f5 26. Nb4 Rc5 27. Na6 Re5 28. Nc7 g6 29. Rb1 Re7 30. Nd5 Be5+ 31. Kg5 Rd7 (31... Kg7) 32. Nf6 Kg7 33. Nxd7 (33. Ne8+ Kf7 34. Ng7) 33... h6# 0-1

I like the move O-O

O-O