Where do you think your opponent went wrong? 8...Nbd7
It's a trap! Early forced mate

Your opponent seems to enjoy moving pieces multiple times in a row in the early stages of the game. This may not have lost him the game, but it certainly didn't help him. Nice game.
After 15... f5 16. Rh3
After Black's next move (doesn't matter what he plays), White plays Rf1 and now Black is definitely done. That's why on move 15 I cited my clear back row as one of the reasons for the forced mate; no matter what Black plays, the rook comes over and seals it. For example, Black could attempt to exchange Queens by clearing the f-file and then bringing his Queen over, but after checking the King at h7 or h8 Rf1 would skewer the Queen.
Oinquarki, I think my opponent's rating is 1464. I'm currently at 1598.
Same thing. f6 or f5 are Black's best moves at this point, but once my second rook becomes active it's curtains.

Part of the point of 15 ...f6 or ...f5 is to give black's king room to dodge back behind his Rf8. This is a common enough theme in this sort of attack. So white has sacrificed material for, admittedly, a strong attack, but not a fatal one. I like black's chances here.
After reviewing the game, Qe8 is the only move that saves Black. However, this does not stop White's attack: after 15... Qe8 16. Rh3 f5 17. Qh7+ Kf7 Rf1 Black's position is still in shambles, and with all the combinations I can come up with White always goes ahead in material.
After reviewing the game, Qe8 is the only move that saves Black. However, this does not stop White's attack: after 15... Qe8 16. Rh3 f5 17. Qh7+ Kf7 Rf1 Black's position is still in shambles, and with all the combinations I can come up with White always goes ahead in material.
... after f5 or Qe8 then f5, and you move your second rook to f1....
how are you supposed to win?
I think Black should win this game.

The best white can do in the last position is a draw by perpetual
for example:
15.Rf3 dxc4 16.Rh3 f5 17.Qh7+ Kf7 18.Qh7+ Ke7 19. Qh4+ Kf7 ...

After 15... f5 16. Rh3
After Black's next move (doesn't matter what he plays), White plays Rf1 and now Black is definitely done. That's why on move 15 I cited my clear back row as one of the reasons for the forced mate; no matter what Black plays, the rook comes over and seals it. For example, Black could attempt to exchange Queens by clearing the f-file and then bringing his Queen over, but after checking the King at h7 or h8 Rf1 would skewer the Queen.
Oinquarki, I think my opponent's rating is 1464. I'm currently at 1598.
I cannot see a mate after 16. Rh3 , for example 16. ... Qe7 17. Rf1 dxc4 18. Rff3
Qe8 19. Qh4 Kf7 . What is your variants ?
Interesting game I played a while back. One of my main deficiencies as a player is my relative inability to calculate combinations, and therefore, play complex traps and attacks. This time I managed to pull it off, with a rather innocent looking move resulting in forced mate before move 20.