Why 3. d3? The e4 pawn wasn't being attacked, so you could have done something more active like Bc5 or Nc3 or even d4.
The bishop sac doesn't seem good. I'd say 10. Qf3 was a mistake as well, given that you probably want to keep your queen to try to make something of black's loose king. After move 11 in the game, black's king is a bit open, but there's no real way to attack it as far as I can see, meaning you're simply down ~2 pawns.
Good post-game analysis on move 20. Those quiet moves can be hard to spot.
Thanks for the comments. I still don't know why I played the bishop sac in the first place. I think I was mostly irritated at the prospect of having to retreat the bishop and waste a turn so I wanted to think of something else.
As for why I played 3. d3, my mouse slipped. Totally not making that up.
