Critical Moves Played Too Fast
Opening: D00: Queen's Pawn Game
After an unusual but fairly equal opening, Black decides to castle opposite sides, creating a major imbalance. Both sides start attacking when Black sacrifices a piece - on the side of the board where his king is! After that White is winning but Black manages to create some complications. Eventually White goes wrong and Black gets an attack. Then White unnecessarily weakens his king and Black gets serious threats. With both sides playing very quickly compared to the 30-30 time control (at the end of the game the total time remaining on both clocks is about the same as it was at the start of the game due to increment!), White goes badly astray and manages to resign just before being checkmated.