Against 1e4, I played a fun line in Nimzowitsch defense. One of the aspects I enjoy in this variation is the limited options that white has, even though white is following opening theory. The idea stems with closing the center, and targeting white kingside. Some minor tricks can occur, but it's mostly a straightforward layout. Unfortunately in this game, white blunders an entire knight. While that occurence doesn't happen often, I was fortunate enough to see just how far black could punish white after capturing 13 (Bc2, Qxg5).
Key points: blunder, middlegame tactics, and ripping open the kingside.
[Event "YC007 vs infermate"]
[Termination "infermate won by resignation"]
1. e4 Nc6 2. d4 e5 3. d5 Nce7 4. c4 Ng6 5. Bd3 Nf6 6. h3 Bb4+ 7. Nc3 O-O 8. Nf3 Bxc3+ 9. bxc3 d6 10. O-O b6 11. Be3 Nh5 12. Ng5 Nhf4 13. Bc2 Qxg5 14. g3 Bxh3 15. Re1 Nh4 16. Kh2 Bg4 17. gxf4 exf4 18. Rg1 Bxd1 19. Rxg5 Nf3+ 20. Kg2 fxe3 21. fxe3 Nxg5 0-1
So black campaign began.
14 (g3, Bxh3) Pawn is pinned against King, and knight is protected with pawn to maintain pin for equal trades if white chose. This pin allowed a sneaky bishop threatening the rook.
15 (Re1, Nh4) Rook evades threat, while second knight joins the attack securing a safe square for when
16 (Kh2, Bg4) king moves to one odd the squares unpinning the pawn and threatening black knights, however because of the "free" knight earlier black is less concerned and targets white Queen with bishop!
17 (gxf4, exf4) white picks a knight believing white can win a bishop, but it's not so easy when
18 (Rg1, Bxd1) white Queen is captured!
19 (Rxg5, Nf3+) Rook captures black Queen, but knight gains tempo checking the king while threatening rook!
20 (Kg2, fxe3) pieces are hanging, and white only has enough time to capture one of the remaining pieces
21 (fxe3, Nxg5) and white resigns.
After the exchanges, and the dust settled, black was up a rook and had a clear path to march pawns along the far kingside for promotion as one plan for the endgame.
I hope you found value in this game.
Listed below is a link for your own analysis.