Hi - my sister came to my appartment to wish me a merry christmast with her friend and her boyfriend. I've never seen that guy in my life, and he sees my chess sets and asks me 'are you good at chess ?' I answer, i don't know, trying to get better everyday, what about you ? He pretends he's a deadly attacker and that he could probably beat me - he wants to play.
I accepted without much confidence about myself, he was intimidating -  we decided it to be a 20min game - i've been studying chess for almost 7month now - i told myself i should maybe beat him - the only problem is that i really did not know how good he was

I used Nimzo indian defense, because i am reading a book about it and i'm halfway done - i still have problems finding mates, so i'm glad he resigned.

I've win the game, but i want to know if i've miss some good moves.
Thanks for reviews, much appreciated.

Maat> First attack that seemed so pointless in my eyes - he trades his dark bishop for my knight.

We could discuss the intracacies of the opening, but we're not experts on the Nimzo-Indian, and I doubt it will matter much to the outcome of your game. For what it's worth, 4...Nc6 and 5.Nxc3 both appear to be second-best moves to my eye. I mean, 4...Nc6 blocks the c7-pawn and I would aim instead for 4...c5!? 5.dxc5 O-O 6.a3 Bxc5. 5.Nxc3 seems to resolve the tension prematurely; my preference would be 5...O-O 6.a3 Bxc3 7.Qxc3 Ne4. GMs play the first line so matters may not be so simple as they first appear.

But let's get serious and look at tactics, which decide most amateur games.

Maat> 9...Nxf2? 10.O-O? - "I bet he did not see that one coming."

Neither did I. You missed a chance to win a piece for a pawn 10.Kxf2 and now what were you afraid of? 10...Nxd3+ 11.Qxd3 and you win. 10...Qh5+ was impossible since your knight protects that square. Now you're the one in trouble.

Maat> 11...Qxa3 - But oh wait, he trades queen off What is he trying to do. 

He's up material. When you're up material, you trade pieces to win.

Maat> 12...d5?

12...Nxf2 was easily winning for Black. He would be up an exchange, a pawn, have saddled you with doubled pawns, plus the queen are off!

Maat> 14...a5 - but he declines - too bad, it's game over

Yes, he hung a piece, and he continued to hang pieces that you scooped up. You do seem to be quite a bit stronger than your opponent.

Maat> 27.d5??

Giving away your knight for free, but still winning.