If 28...Nf5, then 29. Nxf5 Bxf5 30. Bxf5 gxf5 31. Qg5+ Kf7 (if 31...Kh8, then 32. Qh7#) 32. Qg7+ Ke6 33. Qd7+ Kxe5 34. Rd5+ Kxf6 (if 34...Ke4, then 35. Qxf5#) 35. Rxf5#.

The famous Pillsbury-Tarrasch game is analysed in Vukovic's book on the Art of Attack. Vukovic thinks it's quite a tight struggle with chances for both sides.

<"My latest anti-Nimzo-Indian variation. It has the merit of being completely untried at master level and, having played it all of three times, I am now undoubtedly the worlds leading authority on it. Indeed, after one or two more it will probably be named after me!">

This game is full of deep calculations but thanks to the very instructive annotations, even a novice chess player such as me can follow what is going on.

<An Englishman> I had a similar reaction to yours. But here is what Vuckovic has to say after his seven pages of annotations on the Pillsbury-Tarrasch game:

<This famous game has taken its place in chess literature as a classic example of an attack on the castled king which is stronger than the counterattack on the queenside. But in light of my annotations, which differ fundamentally from all annotations hitherto, from Tarrasch to Reti, this game takes on a new appearance. Black's numerous opportunities to strengthen his game at various stages point rather to the equal balance between attack and indirect defense, and it was only the decisive mistake on the thirty-eighth move which swung the balance in White's favour. This view of the game also qualifies it as a good example of the importance of indirect defence against an attack on the castled king, and of the part played by operations with wing pawns in particular.>

Vukovic then makes an interesting assertion:

<Indirect defense by means of advancing a pawn majority on the queenside was at one time held in high esteem and was more often practiced than nowadays; the real reason for this is that we have acquired a better understanding of the centre and the technique of centralization, thanks to the hypermodern school. It is clear that the player who has a majority on the wing, when the material is equally balanced, will usually not have the greater influence of pressure in the center, nor whill he have the necessary conditions for a central action. A majority on the wing is created at the expense of the centre and means giving up lateral pressure on the centre, and that is the sort of strategy which the masters of today are reluctant to adopt.>

Perhaps you could say that you see "indirect defense" in Vukovic's sense as practiced by Pillsbury and Spassky today more in positions in which the center pawns are locked, as in the classical King's Indian, where white advances his queen-side pawns and defends his king.

But here is an example from a QGD in which a queen-side pawn advance fared better:

Pillsbury vs Schlechter, 1895