13. Qxd4 ends it much earlier.
13. Qxd4? can be answered by 13...Nc2+, winning back the queen.
17...Kxb7 18. Bf3+ Nc6 19. Qxc6+ Kb8 20. Bf4+ e5 21. Bxe5+ Qd6 22. Bxe6#
If you need help, please contact our Help and Support team.