Indeed - but it seems that Black missed a draw by 33...Qh6 (instead of Re7?): 34.Rxd5 Bb7! <34...Qxh8? 35.Rg5+ Kf7 36.Qd1 (threatening both Qxc2 and Qd5+ with mate) Bb7 37.Qd7+ <37.Qxc2?? Re1#> Re7 38.Rf5+ Qf6 39.Rxf6+ Kxf6 40.Nxh5+> 35.Rxh5 Rec8 36.Bb2 Qc6 and White doesn't seem to have anything better than forcing a perpetual with 37.Rh8+ Kf7 38.Rh7+ Ke8 <38...Kg8?? 39.Rg7+ Kf8 40.Ba3+> 39.Rh8+ Kf7 etc. (37.Rd5 Rxb2; 37.Nd5 Rc1+ 38.Bxc1 Qxc1+ 39.Qxc1 Rxc1+ 40.Kg2 Rd1)

However, the good thing is, there is a much easier way of getting the upper hand. It is more positional but it is very (if nor more) interesting and instructive. Plus it allows White to take his time to build up an attack. I admit I discovered it via Shredder. However, it does not require much calculation though it is a bit of a tricky move to find.

15. b3-b4!! My eyes nearly popped out when I saw this beauty. Quite cool isn't it? Many pieces on the board and Black is already in a sort of Zugzwang.

Black's response 1: do nothing about the central pawns. White's plan is simply cxd5 (threatening d5-d6) then follow up with bxc5 with a passed pawn, secure queenside + heaps of space, and a Kingside attack to brew up.

Black's response 2: ...bxc4
Here is a dilemma bxc5 or dxc5? Either way Black's light squared Bishop is pretty useless. Personally, I'll prefer bxc5, ditch the Kingside attack idea and pawn storm the Queenside. With Black's pieces all in the way of each other, it'll be awesome (if you are White, that is;) )

Black's response 3: ...cxb4.
White's answer is obvious: 16. c5.
Again, passed pawn. White can Kingside attack, pick up Black's pawn or/and Nb3-a5 (or other knight maneouvres on the Queenside to block squares while choking black up and attacking his Queenside).

Black's response 4: ...cxd4.
Even easier. Again, 16.c5. White can then centralize Knight and pick up the pawn on d4 at the same time.

IN CONCLUSION: If you play 16.c5 instead of Shirov's option of releasing the central tension, you are a stronger player than him ;)