why did my opponent resign here?

[White "sudhi76m (1380)"]
[Black "jonnyjacks299 (1360)"]
[Result "jonnyjacks299 wins by Resignation"]

1. e4 e5 2. Nc3 Nf6 3. h3
{INACCURACY (-0.39) A better move was 3. Nf3} ({(+0.13)} 3. Nf3 Bb4 4. Bc4)
3... Bc5 4. Bc4 c6 5. a3
{INACCURACY (-1.11) A better move was 5. d3} ({(-0.36)} 5. d3 d5 6. Bb3)
5... d5 6. exd5 cxd5 7. Ba2 d4
{INACCURACY (-0.19) A better move was 7... Nc6} ({(-0.87)} 7... Nc6 8. d3 O-O )
8. Nce2 d3 9. cxd3 Qxd3 10. Nf3 e4
{MISTAKE (+1.84) The best move was 10... Nc6} ({(-0.42)} 10... Nc6 11. b4 Bb6 )
11. Ne5 Qa6
{INACCURACY (+2.26) A better move was 11... Qb5} ({(+1.43)} 11... Qb5 12. Nxf7 Rf8 13. b4 Bxf2+ 14. Kxf2 Qb6+ 15. d4 exd3+ 16. Ke1 Rxf7 17. Bxf7+ Kxf7 18. Qxd3 Be6 19. Rf1 Nd7 20. Be3 Qc6 21. Nd4 Qd6 22. Qe4 Bd5 23. Nf5 Qe5 24. Qxe5)
12. Bxf7+ Ke7 13. Kf1
{BLUNDER (-0.87) The best move was 13. Bc4} ({(+2.52)} 13. Bc4 b5 14. Ba2)

{Game could have continued}
({(-0.87)} 13. Kf1 Bd6 14. d4 exd3 )

cuz he meant to castle and had a mouse slip? that's my guess.