2k vs 4k game review

This game was played at an online tournament.

I was playing black (4k) against white (2k) and lost by time (I got into 30 second byo-yomi relatively soon in the game. These are standard 30min + 5 x 30s games). However at that point white was comfortably ahead and black was desperate.

My general feeling is that I generally played well the first half of the game (save for a corner 3-4 joseki where I seem to have screwed up but somehow managed to come out pretty decent anyway), but screwed up the second half. I would love to hear opinions from strong players so that I can focus on my mistakes.