Out of the Blue.

The ending of this game was a bit shocking.  Throughout the game I was doing well - which the computer confirmed - then suddenly, blam, checkmate.

What was the mistake I made?  Most of the action was in the centre and queen-side, and my opponents second to last move looked like a silly defensive move - but I was so wrong.

Two things I learnt from this game: first, I need to be more aware of aligned pieces and what they threaten; second, the computer analysis can be wrong.  This second lesson comes from the computers post-game analysis where it measured my last move as improving my position.