Failing In Tactics

Over FICS, I played against a 1500 rated player and promptly lost despite having an advantage. Bummer!

Here's the position with Black to play.

This position arose from a Reti opening (yes, I do play the Reti Opening). Black has a positional advantage and White's pieces are currently tied up in knots. The White Knights have no good squares to relocate to, the Rooks are passive, the Queen is passive.

And being the absolute idiot that I am, I played 26... Bxb2?? An error of humongous proportions. Do you know why the b2 pawn is taboo?

....... You've probably seen it by now. Because of 27. Ne1 and it's goodbye Bishop! From that point on, it was pretty much downhill all the way.

In this position, I should have played a far stronger move.

Can you see what should Black do to press home the advantage?

Please stop reading now if you do not wish to know the answer.

The correct response is 27...f4!! White has a couple of responses. None are good.

a)
28.exf4 Bxf4! (see 2nd diagram on left) threatening Bxc1 and Bxg3+ forking King and Queen. The Bishop cannot be recaptured because of Re2 winning the Queen



b)
28. Qf1 fxe3
29. Qxd3 Rxd3
30. Ne1 Rd2+!!
31. Nxd2 exd2
32. Rb1 Bxg3+! (see 3rd diagram on left) and Black wins (Rxe1 is coming and no force on earth can stop the d-pawn from Queening)

c)
28. Kg2 fxe3
29. Qf3 e2
30. Ne1 Qd1
31. Rc2 Bd4
32. Nxd4 cxd4 (see 4th diagram on left) and Black wins as the next move is d3->d2 and White is powerless to stop one of the pawns from Queening.

Oh well, back to the drawing board!