An interlocked pawn structure

Here is another recent interesting situation that I got involved in, in my OTB chess "career" (please don't laugh.) 

Basically I am black in this game.  The topic title is perhaps slightly true but also slightly misleading.  Perhaps the topic title should have been:  "how my opponent messed up an interlocked pawn structure!"  He shall remain nameless although I suppose if anyone was so inclined they could search the ECF grading database in July! 

Anyway my opponent commented after the match:  "It was just one bad move by me."  I replied bluntly but also truthfully:  "Yes you completely messed up interlocking the pawn structure." 

My opponent was only a few moves away from a dead drawn position from the opening position.  Had he played f5+ and then played h3, and then moved the King over to prevent Nb4 it would have meant pointless waiting moves between the two of us.