This move is weak. It opens no lines and does not have any influence on the center. a4 would have been a little better, since it opens the a-file for the rook.
2... d5 3. e5 c5 4. c4 Nb8c6
attacking e5
5. Ng1f3 b5
This costs one pawn, because there is no compensation after capturing the pawn.
6. cxd5 exd5 7. Bf1xb5 Bc8d7 8. O-O a6
New idea: Qe7 --> increases the pressure on e5.
9. Bb5a4 c4
Now (some time after the game was actually played), I believe this move is wasted. This position can't be maintained, because the b- and d-pawns can easily attack this one. Additionaly, only 2 pieces have been developed so far. g6 (to allow Bg7) or Ne7 are better.
10. Nb1c3 Bf8c5
This bishop is easily attacked with b4. Either it moves directly or after 11. b4 cxb3 e.p. 12. d4. White gains control in the center. Furthermore, the knigth attacking d5 was overlooked.
11. Nc3xd5 Ng8e7 12. Nd5xe7 Qd8xe7 13. b4 Bc5d4
This moves leads to a black knight on the wrong place.
14. Nf3xd4 Nc6xd4 15. Bc1b2 Qe7xe5
Not so good. This pawn was actually defending the black king against white threats on the now open e-file. Moving the knight is probably better. Or Bxa4 Qxa4, followed by Nb3. After that, safe castling would be (finally) possible.
16. Qd1e1 Qe5xe1 17. Rf1xe1 Nd4e6 18. Bb2xg7
The result of an earlier mistake. Safe castling and hiding the king is no longer possible.
