Data Fly is correct.
23...Rxf3 is the move here. Black wins a piece as capturing on f3
allows a Black mate or a loss of the Queen.
Looking the at the previous moves it does appear Rxf3 could have been
sooner before even Nh4.
It is possible Black saw Rxf3 but quickly rejected it because it open
the g-file towards his King.
During the middle game White seemed to be playing random move chess.
He should have played Qxh6 after Bxh6. He may have created a problem
or two although he had no valid follow up for the piece sac.
Instead he jumped from plan to plan and it's hard to figure out what
he was up to. His Ra3 was played to get in that check on g3 which
infact was a severe blunder and he resigned the next move.
3....Bc4 is OK. As Data Fly says, 3...Nf6 hitting the e-pawn can lead to
some hairy positions but so can 3...Bc5 if White plays an Evans with 4.b4.
The difference between 3...Bc5 and 3...Nf6 is down to a matter of taste.
As White if I've played 3.Bc4 I slightly prefer to see 3...Nf6 as I'm booked
up the eye brows on that. 3....Bc5 I use to player the Evans or the 4.c3 and 5.d4 lines.
Here is fun game.
G.Chandler - K.Davidson, Edinburgh 1979