Spoiler alert.

Playable, but unambitious.

...unless you intend to play the Q on the center of the board for the rest of the game (you can explore this option for long, but I'd say that this Q situation is bad unless he finds shelter on f2. This is not easy for white to accomplish, and it will make his game a struggle.

Probably this retreat is prudent, though it does suggest that the knight recapture on d4 ought to have been preferred.

Interesting strategic decision. See my next comment.

The best (re)capture in my view. Taking with the knight would have led to the exchange of knights and possibly the queens as well. That would have made the isolated d-pawn more of a liability than it is with those pieces remaining on the board. At the cost of the strategically problematic d-pawn, Black gets quick development and attacking chances behind the lines. That d-pawn is not a complete liability at that: controlling the useful e4 and c4 squares, and providing just enough cover for Black's mobilization. I'd marginally - but only marginally - prefer Black here.

Very interesting. Black is not interested in fair exchanges. Plus, he kind of forces e3, being threatening d4.

Because of what follows! ...d4!

How about 10.Nd5 Qd6 11.e4 dxe3 e.p. 12.Nxe3.

I just went to comments to propose Nd5 in view of this line. Now, thanks to archduke, I understand that the threats are far more complex than I saw before. Black can try 10... Qg6. If white goes for the R with Nc7+, Kd8, 11. NxR, will lose for sure since his K is set for a strong attack starting with 11... Bb5+, 12. Nd2 (ORO= only reasonable option), with motifs similar to the game's. Ok. BUT what if white doesn't go for the R inmediately, and plays (10. Nd5, Qg6, 11. Qa4 instead? It prevents Bb4+, and if ...Bd7, 12. Nb6, with the idea of NxBd7. (Of course, the N is untouchable due to QxR+). Black can try Bb4+, but now 13. Kd1 and the WK is still ok. . If black moves the R, White goes Nd5.

Black starts a mating attack, almost thematic. Very well executed.

I have a feeling this was the wrong knight...

...with the other one, the attack would have been successful all the same, I'd dare to say.

White is probably lost already. These kind of Qside weakness is what made me desist to play c4 with white (I mean: it's playable, but the game goes to a complete different path if white plays c3)