I played this short game with 15|0 time control. My opponent castled queen-side, which is a positional blunder - c-file can always open up in Queen's gambit and white has no problem marching a and b-pawn down the board. Or at least b-file if opponent plays Nimzo-Indian and exchanges bishop for knight very early. Even if he didn't make all the other blunders, I think that attack on his king would win the game in the long run.

Engine gives white 1+ advantage after 8...0-0-0, so I'd like to hear some opinions if 0-0-0 puts black in losing position (not straight-away losing of course), as I think, or is white just going to win one pawn, as engine thinks.

Well, he castled queenside.

But if you hadn't brought your queenside pawns up, he would have lasted longer.

It's quite funny how your opponent left his queen hanging. Didn't he notice the bishop?

It's ok to castle queenside in certain cases.

His opponent left his queen hanging on purpose. If the queen moves black gets checkmated.

I think 0-0-0 is a mistake but not losing. 0-0-0  combine with his slow play of f6 and e5 is what really finished him quickly

I think his thinking process after 14.Bxb4 was:

"Where to move the queen, where to move the queen... Oh, darn, he's got checkmate threat... OK, how to prevent the mate, how to prevent the mate...

*14...e6 15.Bxd6*

Oh, right, the queen..."

The move that doesn't lose the queen is 14...Qc6, it exchanges the queens and wins some other material for me. He had all but 2 pieces on queen-side (let's say queen included), so he could defend after castling. But I think his position would still be too much of a mess after middle-game.

In the heat of it all it wouldnt surprise me if he thought Qc6 lost to Ne7+, totally forgetting his N on g8, which he did all game anyway.

That's very likely, I myself noticed this fork during the game and almost forgot that he has knight on g8.

I started playing a lot of 15|0 games lately, I usually play 2-3 in a row right after I come home, and now I understand why some people are addicted to live chess. I played this Queen's gambit today (the game below) and I think it shows what can happen if you take ability to castle from your opponent.

I played this game quite well, always making top-3 moves for the main part of the game. However, I tend to lose interest when a game is already won for me, missing mates in 2 and such...

There's nothing wrong with simplifying into a winning endgame! Especially in a tournement. Why risk trying to calculate an 8 move mate and getting it all wrong and risk losing, when you can simplify into something that is much easier to convert? Of course you know this already, I was just making my point clear!

Your opponent screwed up the opening and you took advantage - good job!