xombie: Beautiful game, much of which I don't understand.
Position after move 15: Black has open b file, blocked Bg7, potential f5 break (which is never played). Had this occurred in one of my games, I might have been nervous, owing to b3 hole, b file action and square creation if b4 by white.
But note that the b4 break is obviousness in itself, and it is based on which white's whole strategy rests, in conjunction with the weakness on a6 and the fact that c5 cannot be occupied. Black's pieces are too disorganized to sit on c5. However, black still has f5, and for reasons that are not apparent to me, does not play it. I think f5 is met by exf5 and f4 maybe.
Anyway, back to more obvious ramblings. 16. Bh3(!) anticipates movement of knight, prevents f5 indirectly (for he can then fix the pawn with f4 and attack it with Nh4. Also, effects trade after knight moves - excellent considering that the Bc8 is often the cause of grief in KIDs. It also leaves black with the very useless Bg7.
One possible plan for white is to anticipate f5 and then nullify the Bg7 with f4 .. e4 and Bc3, but this does not seem to bite much I think. If I interpret this correctly, the key is to prevent f5 - which is done brilliantly with 20. Ne3!. Point is, 20 ... f5 leads to the preventive combination 21. exf5 gxf5 22. Nexf5 Rxf5 23. Qe4 which wins the rook (I wish I could see those in my own games - I've been very proud of them when I get them).
After f5 is prevented, white goes ahead with his own plans. b4, etc, and collapse occurs.
Can someone explain the purpose of 26. Kg2? It either has to mean 'pass' or something else (such as denying the Q the h3 square). I also think that black is close to zugzwang at this time.
This tells us that black was already nearly lost by move 15, or needed something active and dangerous.