Blunder by opponent, help me out with the rest

1. d4 e6           I assumed this would transpose into a regular opening

2. c4 Nf6         Looks like an Indian!

3. Nf3 Nc6       With this move we're outside the book 

4. Bg5 Be7       We continue to follow some basic QGD ideas from here 

5. Nc3 Ng4

6. Bxe7 Qxe7

7. e3 Qb4        I'm continuing on the basic QGD structure, Qb4 is I guess a developing move  

8. Qd2 O-O

9. a3 Qd6

10. Ne4 Qe7

11. Be2 d5

12. Neg5 h6

13. Nh3 b6

14. cxd5 exd5

15. Rc1 Na5

16. Qc3 Nf6

17. b4 Ne4

18. Qxc7 Qxc7

19. Rxc7 Bxh3

20. gxh3 Nb3     

21. Rg1 Rac8      I should have protected the open file with Ba6

22. Rxa7 Rc1+    I think I can avoid a trade, gain a pawn, and maintain my defence. I'm wrong

23. Bd1 Nc3       I must abandon my bishop or lose

24. Kf1 Rxd1+

25. Kg2 Rxg1+    Opponent trades down now that he's ahead

26. Kxg1 b5

27. Ne5 Nd2

28. Kg2 Ne2

29. Rc7 Ne4

30. h4 f6

31. Ng6 Rf7       Opponent tries to trade down again, missing forced mate

32. Rc8+ Kh7

33. h5 {Nonoruego resigns} 1-0

This seems like no major blunders other than what I noted, move 21 where I take the open file right in front of his king seemed promising, but let to disaster.