Qxa4?

I guess because of this line: 22 bxa4?? Rb8+ 23. Ka1 (23. Kxa3 c4#) 23 ... Nc2#. Although, of course, the straightforward 21... Qc3+ 22. Kxa3 c4# seems more to the point (especially since it uses the same core idea).


You're right. Regardless, 12. ..Re8 is hands down the best move for black in his position.
After
12. ..Re8
13. Be3 cxd4
14. Nxd4 Bb4+ !
followed by
15. ..Bc3
White has lost both his castle and the exchange
I was gong for the mate. I saw it, but rebuffed it.