This game was my most recent Petrosian formation. It was presented at Mike Splane's chess party the Sunday before last, and I am reasonably happy with the insight.
It is hard for me to say where black went wrong here. The usual KID plans for both sides were being played - black restricting white's queenside expansion plans with a5, Bd7, Qe8 and Nc5, while white plays for a3+b4. White carries out the a3+b4 push, but due to a tactical circumstance, the natural knight move to a5 (after b4 attacking the Nc5) meets with a strong knight trapping move Nb5, after which the knight is surrounded and will soon be captured. Black livens up matters by causing some nuisance problems in the center. White trades his queen for the two black rooks. In the ensuing position, things are resolved with a few tactical sequences - the first, to induce black to weaken his diagonals, and then white clears off a few pawns and creates a passer, supported by the bishops. The final promoting sequence involves an overloaded queen that is overcome by a tactical shot.
This was overall a pleasant game for me to have played. However, I believe that the databases do not approve of white's opening early on.