2)

13...Nbxd5 14 Bxd5 Nxd5 15 Nxd5 exd5 16 Rxd5

Did you analyse this far and decide Black was lost? He has a spectacular resource:

16...Bg4! 17 Qd3

17 Qc4 would be answered in the same manner.

17...Qxd5! 18 Qxd5 Rad8

White’s back rank costs him his queen.

19 Qb3 Rd1+ 20 Qxd1 Bxd1 21 Be3 Bb3 22 a5

22 Bxa7 Ra8 regains the pawn.

22...a6

White must even be a little careful here not to be worse.

23 Nd7 Rd8 24 Nc5 Bd5 25 Rc1 Rd6 26 f3 h6 27 Kf2 Bh4+ 28 g3 Bd8 29 Rd1 Be7 30 Nxa6 bxa6 31 Bc5 ½-½