Denver Open- What did I do wrong?

I thought I played a great game, I was ahead most of the game-but I just couldnt pull it off. I know there was a few mistakes I made, and I'm pretty sure there was something different I could have done to pull off the win. This was my 1st real tournament, and a pretty tough competition, so I was a little nervous. It was G/90+30sec, so I had plenty of time. Ended the tournament 1-4-0, but I only beat another unrated, so still no rating for me :(

My annotation is pretty poor, I was in a bit of a rush- Im sure I could have done a better analysis of my own game, but like I said, I just started playing for a rating. Any help and ideas would be appreciated

 Had to Redo the notation since I closed the page when I first submitted it, so there is even less, but the key move thoughts are in there, as well as a few other lines. I have to go to work. Sorry for lack of insight

For the record: That wasn't a win, you took a bye in the 3rd round. That is why you didn't earn any rating points with that 1pt Bye. Looking at your recent chess.com games, you clearly have improved since then. You are at least 1300 USCF. Playing against my buddy, Catholic Batman,  has sharpened you up. Btw, You did better in the 2nd tournament. I helped direct that one.  That was the Colorado Open. It was bittersweet for me. We had some troubles with long entry lines and frowny faces because some players did not plan ahead and send in their entry fee in advance - as a result - First round  started late.  But, It was a record turnout, and I met GM Yermolinsky. Why aren't you still playing in tournaments? Get back in there.

Other than being in Denver?

6...Kf4 and it is black who wins.

4.g4 is interesting but a better follow up is 5.Kxb2.