Is computer analysis rubbish or am I missing something?

I am black. Please see my "mistake" on move 12 and computer's suggested moves. Isn't last move suggested by computer allowing white to take my rook?

http://www.chess.com/home/computer_analysis.html?id=43097547&game_type=1

Copy and paste the PGN file into the game editor.

I pasted the PGN in resources analysis board - but analyed suggested moves do not show up when I step though. Any ideas how I can show them?

Here's the game in question since the link provided by Skand doesn't seem to work now: http://www.chess.com/echess/game.html?id=43097547 (I found it on the basis of game id, I'm quite a hacker, I know :) )

Skand, can you please publish the analysis in question here (The variation proposed for move 12)?

 An attacking move. I like it!

There are two PGN files. One is on the game page, the other can be accessed by first clicking on "Computer Analysis" and picking up the one therein:

This PGN file will come complete with computer analysis.

[Event "Ray Duque III - New Year Team Match - Board 16"]
[Site "Chess.com"]
[Date "2011.01.16"]
[White ""]
[Black ""]
[ECO "D35"]
[ChesscomGameID "43097547"]
[Annotator "Chess.com Computer Analysis"]
[Result "1-0"]
[WhiteElo "1939"]
[BlackElo "1822"]
[TimeControl "1 in 3 days"]
[Termination ""]
{Inaccuracies(?!): 12 = 20.3% of moves | Mistakes(?): 3 = 5.1% of moves | Blunders(??): 2 = 3.4% of moves}

1. d4 {(Book Move)}  d5 {(Book Move)}
2. c4 {(Book Move)}  e6 {(Book Move)}
3. Nc3 {(Book Move)}  Nf6 {(Book Move)}
4. a3 {(Book Move)}  a6 {(-0.01)}
5. c5 {(-0.15)}  Bd7 $6 {(0.19) INACCURACY - Perhaps better was 5... Nc6}
({BEST MOVE (-0.12)} 5... Nc6 6. Bf4 Nh5 7. Bd2 g6 8. Nf3 Be7 9. Qb3 O-O   $10)
({INACCURACY (0.19)} 5... Bd7 6. Nf3 Nc6 7. Qb3 Na5 8. Qb4 b6 9. Bf4   $10)
6. b4 {(-0.47)}  Nc6 {(-0.53)}
7. Bg5 {(-0.53)}  h6 {(-0.51)}
8. Bh4 {(-0.48)}  Be7 {(-0.41)}
9. e3 {(-0.47)}  b5 $6 {(-0.04) INACCURACY - Perhaps better was 9... O-O}
({BEST MOVE (-0.44)} 9... O-O 10. Nf3 Ne4 11. Bxe7 Qxe7 12. Nxe4 dxe4 13. Nd2 e5 14. Nxe4 exd4   $15)
({INACCURACY (-0.04)} 9... b5 10. Bd3 e5 11. Bxf6 Bxf6 12. Nxd5 exd4 13. Nxf6+ Qxf6 14. Qf3 Qxf3 15. Nxf3 dxe3 16. fxe3   $10)
10. Bd3 {(-0.04)}  e5 {(-0.1)}
11. Bxf6 {(-0.22)}  Bxf6 {(-0.22)}
12. Nxd5 {(-0.11)}  h5 $2 {(0.89) MISTAKE - With that last move you went from roughly equal to having a worse position. Your best continuation was 12... exd4}
({BEST MOVE (-0.28)} 12... exd4 13. Nxf6+ Qxf6 14. Qf3 Qxf3 15. Nxf3 dxe3 16. fxe3 a5 17. Kd2 axb4 18. axb4 Rxa1 19. Rxa1 Nxb4   $10)
({MISTAKE (0.89)} 12... h5 13. Nxf6+ Qxf6 14. d5 Ne7 15. Qf3 Rh6 16. Qxf6 Rxf6 17. Nf3 Nxd5 18. Nxe5   $16)
13. Nxf6+ {(0.91)}  Qxf6 {(0.89)}
14. d5 {(0.96)}  Ne7 {(0.72)}
15. e4 {(0.77)}  g5 $6 {(1.36) INACCURACY - Perhaps better was 15... O-O}
({BEST MOVE (0.87)} 15... O-O 16. Nf3 Bg4 17. a4 Qf4 18. O-O Bxf3 19. Qxf3 Qxf3 20. gxf3   $16)
({INACCURACY (1.36)} 15... g5 16. c6 Bg4 17. f3 Bc8 18. Ne2 O-O 19. O-O   $16)
16. c6 {(1.34)}  Bc8 {(1.68)}
17. Ne2 {(1.57)}  g4 $6 {(2.03) INACCURACY - Perhaps better was 17... O-O}
({BEST MOVE (1.4)} 17... O-O 18. O-O Qg6 19. f3 f5 20. a4 fxe4 21. fxe4 Bg4 22. axb5 axb5 23. Rxa8 Rxa8   $16)
({INACCURACY (2.03)} 17... g4 18. a4 bxa4 19. Qxa4 O-O 20. O-O Rd8 21. Qb3 Rb8   $18)
18. Qc1 {(1.49)}  Ng6 $6 {(2.09) INACCURACY - Perhaps better was 18... h4}
({BEST MOVE (1.62)} 18... h4 19. Qe3 h3 20. g3 Qh6 21. Qc5 f5 22. O-O fxe4 23. Bxe4   $18)
({INACCURACY (2.09)} 18... Ng6 19. O-O Nh4 20. Qe3 O-O 21. a4 bxa4 22. Rxa4   $18)
19. O-O {(1.96)}  h4 {(1.97)}
20. f4 {(1.57)}  exf4 {(1.26)}
21. Nxf4 {(1.56)}  Nxf4 $6 {(2.26) INACCURACY - Perhaps better was 21... Qd4+}
({BEST MOVE (1.74)} 21... Qd4+ 22. Kh1 Ne5 23. Qb1 f6 24. Be2 h3 25. g3 O-O 26. Qc2   $18)
({INACCURACY (2.26)} 21... Nxf4 22. Qxf4 Qxf4 23. Rxf4 a5 24. Raf1 axb4 25. axb4 O-O 26. Bxb5 Ra2   $18)
22. Qxf4 {(1.9)}  Qxf4 {(2.17)}
23. Rxf4 {(2.36)}  Ke7 {(2.62)}
24. a4 {(2.14)}  bxa4 {(2.12)}
25. Rxa4 {(2.12)}  Rh6 $6 {(2.94) INACCURACY - Perhaps better was 25... f6}
({BEST MOVE (2.05)} 25... f6 26. Be2 Rg8 27. Bc4 Rg5 28. Ra5 Rb8 29. d6+ cxd6 30. Rxg5 fxg5   $18)
({INACCURACY (2.94)} 25... Rh6 26. b5 a5 27. b6 cxb6 28. e5 Ra7 29. d6+ Kd8 30. c7+ Ke8   $18)
26. e5 $2 {(1.46) MISTAKE - Your opponent made a mistake! Better was 26. b5}
({BEST MOVE (2.96)} 26. b5 a5 27. b6 cxb6 28. e5 Ra7 29. d6+ Ke8 30. Kf2 Be6   $18)
({MISTAKE (1.46)} 26. e5 Rh5 27. d6+ cxd6 28. Bc4 Be6 29. Bxe6 fxe6 30. Rxg4 Rxe5 31. Rxh4   $16)
26... Rh5 {(1.77)}
27. d6+ {(1.39)}  cxd6 {(1.64)}
28. exd6+ {(1.26)}  Kxd6 {(1.61)}
29. Rxf7 {(1.57)}  Rd5 {(1.47)}
30. Be4 $2 {(0.79) MISTAKE - Your opponent made a mistake! Better was 30. Rf8}
({BEST MOVE (1.71)} 30. Rf8 Kc7 31. Be4 Re5 32. b5 Rxb5 33. Rf7+ Kb6 34. c7 Ra7 35. Rc4   $18)
({MISTAKE (0.79)} 30. Be4 Rd4 31. Bc2 Rc4 32. Rf6+ Ke7 33. Bd3 Rc1+ 34. Rf1 Rxc6   $16)
30... Rd1+ $6 {(1.15) INACCURACY - Perhaps better was 30... Rd4}
({BEST MOVE (0.72)} 30... Rd4 31. Bc2 Rc4 32. Rf6+ Ke7 33. Bb3 Rc1+ 34. Rf1 Rxc6 35. Rf7+ Kd6 36. Rf6+ Kc7   $16)
({INACCURACY (1.15)} 30... Rd1+ 31. Kf2 Be6 32. Rg7 Rf8+ 33. Ke2 Rff1 34. Ke3 Rde1+ 35. Kd4 Rd1+ 36. Bd3 Rf4+ 37. Ke3   $16)
31. Kf2 {(1.05)}  Ke5 $6 {(1.96) INACCURACY - Perhaps better was 31... Be6}
({BEST MOVE (1.11)} 31... Be6 32. Rg7 Ke5 33. Re7 Kd6 34. Rh7 Rf8+ 35. Ke2 Rd4 36. Ke3   $16)
({INACCURACY (1.96)} 31... Ke5 32. Ke2 Be6 33. Re7 Rc1 34. Kd2 Rf1 35. Ra5+ Kd6   $18)
32. Re7+ {(2.04)}  Kd6 {(1.97)}
33. Re8 {(2.15)}  Kc7 {(2.18)}
34. b5 {(2.67)}  Rd2+ $6 {(2.77) INACCURACY - Perhaps better was 34... a5}
({BEST MOVE (2.21)} 34... a5 35. Ke2 Rg1 36. Kd2 Rf1 37. Ke3 Kb6 38. c7 Re1+ 39. Kd2   $18)
({INACCURACY (2.77)} 34... Rd2+ 35. Ke3 Rb2 36. bxa6 Ra7 37. Bd5 Bxa6 38. Re7+ Kb6 39. Rxa7 Kxa7 40. Rxg4   $18)
35. Ke3 {(3.23)}  Rb2 {(3.14)}
36. bxa6 {(3.41)}  Rxa6 $2 {(4.95) MISTAKE - That was a mistake. Much better was 36... Rb3+}
({BEST MOVE (3.31)} 36... Rb3+ 37. Kf4 h3 38. a7 g3 39. hxg3 h2 40. Rh8 Bf5 41. Rxh2 Bxe4 42. Kxe4 Kxc6   $18)
({MISTAKE (4.95)} 36... Rxa6 37. Rxc8+ Kxc8 38. Rxa6 Rb5 39. Kf4 Rb4 40. Ra7 Rc4 41. Ke5   $18)
37. Rxc8+ {(5.14)}  Kxc8 {(5.04)}
38. Rxa6 {(5.09)}  h3 $6 {(6.34) INACCURACY - Perhaps better was 38... Rb4}
({BEST MOVE (5.68)} 38... Rb4 39. Ra8+ Kc7 40. Ra7+ Kd6 41. Kf4 Rc4 42. Rg7 g3 43. Rd7+ Ke6 44. hxg3 hxg3   $18)
({INACCURACY (6.34)} 38... h3 39. Ra8+ Kc7 40. Ra7+ Kd6 41. gxh3 Rb3+ 42. Kf4 Rxh3 43. c7 Rc3 44. Kxg4   $18)
39. gxh3 {(6.69)}  gxh3 $4 {(9.17) BLUNDER - Oh no - a blunder! You should have played 39... Rb3+}
({BEST MOVE (6.68)} 39... Rb3+ 40. Kf4 Rxh3 41. Ra8+ Kc7 42. Ra7+ Kb6 43. c7 Rc3 44. Rb7+ Ka6 45. Kxg4 Rc4 46. Kf4 Rc1   $18)
({BLUNDER (9.17)} 39... gxh3 40. Ra8+ Kc7 41. Ra7+ Kc8 42. Bf5+ Kb8 43. c7+ Kxa7 44. c8=Q Rb3+ 45. Bd3 Rb2 46. Qc7+ Rb7   $18)
40. Kf3 $4 {(5) BLUNDER - Lucky you! Your opponent blundered! The best move was 40. Ra8+}
({BEST MOVE (9.34)} 40. Ra8+ Kc7 41. Ra7+ Kc8 42. Bf5+ Kb8 43. c7+ Kxa7 44. c8=Q Rb3+ 45. Bd3 Rb7 46. Qxh3 Re7+ 47. Kd4 Kb6 48. Qh6+ Kc7   $18)
({BLUNDER (5)} 40. Kf3 Rb5 41. Ra8+ Kc7 42. Ra7+ Kc8 43. Kf4 Rb4 44. c7 Rc4 45. Ke5   $18)
40... Rxh2 $4 {(17.85) BLUNDER - Oh no - a blunder! You should have played 40... Rb5}
({BEST MOVE (5.41)} 40... Rb5 41. Ra8+ Kc7 42. Ra7+ Kc8 43. Kg4 Rb4 44. Re7 Kd8 45. c7+ Kc8 46. Kxh3   $18)
({BLUNDER (17.85)} 40... Rxh2 41. Ra8+ Kc7 42. Ra7+ Kd6 43. c7 Ra2 44. Rxa2 Kd7 45. Rc2 Ke7 46. c8=Q   $18)
41. Kg3 $2 {(5.12) MISTAKE - Your opponent made a mistake! Better was 41. Ra8+}
({BEST MOVE (+Mat14)} 41. Ra8+ Kc7 42. Ra7+ Kd6 43. c7 Ra2 44. Rxa2 Kd7 45. Rc2 h2 46. Rxh2   $18)
({MISTAKE (5.12)} 41. Kg3 Re2 42. Ra8+ Kc7 43. Ra7+ Kd6 44. Rd7+ Ke5 45. Bf3 Rc2 46. Kxh3 Rc3 47. Kg3   $18)
41... Re2 {(5.6)}
42. Bf5+ $2 {(4.12) MISTAKE - Your opponent made a mistake! Better was 42. Ra8+}
({BEST MOVE (5.75)} 42. Ra8+ Kc7 43. Ra7+ Kd6 44. Rd7+ Ke6 45. Bd5+ Kf5 46. Kxh3 Re3+ 47. Kh4 Rc3 48. c7 Rc1 49. Bb7 Rc4+ 50. Kg3 Rc3+ 51. Kf2   $18)
({MISTAKE (4.12)} 42. Bf5+ Kc7 43. Kxh3 Re1 44. Kg3 Rc1 45. Be4 Rg1+ 46. Kf4 Rf1+ 47. Ke5   $18)
42... Kc7 {(4.12)}
43. Kxh3 {(4.21)}  Re3+ {(4.21)}
44. Kg4 {(4.27)}  Rc3 {(5.19)}
45. Bd7 {(4.76)}  Rc5 {(4.77)}
46. Kf4 {(4.82)}  Kd6 {(4.82)}
47. Ke4 {(4.79)}  Kc7 {(4.89)}
48. Kd4 {(4.82)}  Rc1 {(4.82)}
49. Ke5 {(4.68)}  Rc5+ $6 {(5.39) INACCURACY - Perhaps better was 49... Re1+}
({BEST MOVE (4.82)} 49... Re1+ 50. Kd4 Rd1+ 51. Ke3 Rc1 52. Ra8 Kd6 53. Kd2 Rc5 54. Kd3 Kc7 55. Ra7+ Kd6   $18)
({INACCURACY (5.39)} 49... Rc5+ 50. Ke6 Rc2 51. Ra7+ Kb6 52. Rb7+ Ka6 53. Ke5 Re2+ 54. Kd4 Rc2 55. Be8 Rd2+ 56. Kc5   $18)
50. Ke6 {(5.42)}  Rc1 {(5.38)}
51. Ra7+ {(5.44)}  Kb8 $2 {(6.59) MISTAKE - That was a mistake. Much better was 51... Kb6}
({BEST MOVE (5.44)} 51... Kb6 52. Rb7+ Ka6 53. Rb3 Ka5 54. Kd6 Rd1+ 55. Ke5 Rc1 56. Kd5 Rc2   $18)
({MISTAKE (6.59)} 51... Kb8 52. Rb7+ Ka8 53. Rb5 Rc2 54. Kd6 Rd2+ 55. Rd5 Rc2 56. Ra5+ Kb8 57. Rb5+ Ka7 58. c7 Ka6 59. Bc6   $18)
52. Rb7+ {(8.94)}  Ka8
53. Rb5 {(8.94)}  Re1+ {(6.6)}
54. Kd6 {(+Mat13)}  Rd1+ {(+Mat10) FORCED_MATE - Now checkmate is inevitable. Your best defense was 54... Ka7}
({BEST MOVE (14.47)} 54... Ka7 55. c7 Rc1 56. c8=Q Rc6+ 57. Ke5 Re6+ 58. Kf5 Rf6+ 59. Kg4 Rg6+ 60. Kf4 Rf6+ 61. Bf5 Rf7 62. Qc5+ Ka6   $18)
({FORCED_MATE (+Mat10)} 54... Rd1+ 55. Rd5 Ra1 56. Ra5+ Rxa5   $18)
55. Kc7 $2 {(14.05) MISTAKE - Your opponent made a mistake! Better was 55. Rd5}
({BEST MOVE (+Mat08)} 55. Rd5 Rxd5+   $18)
({MISTAKE (14.05)} 55. Kc7 Ra1 56. Kd8 Ka7 57. c7 Rg1 58. c8=Q Rg8+ 59. Ke7 Rg7+ 60. Kd6 Rg6+ 61. Be6   $18)
55... Ra1 {(13.61)}
56. Kd8 {(+Mat06)}  Ra6 {(+Mat04) FASTER_MATE - Now checkmate is inevitable. Your best defense was 56... Ka7}
({BEST MOVE (+Mat05)} 56... Ka7 57. c7 Re1 58. c8=Q Re8+ 59. Kc7 Rxc8+   $18)
({FASTER_MATE (+Mat04)} 56... Ra6 57. c7 Ka7 58. c8=Q Rb6 59. Ra5+ Ra6 60. Rxa6#   $18)
57. c7 {(+Mat04)}  Ka7 {(+Mat03)}
58. Rb4 {(+Mat08)}  Rh6 {(+Mat04) FASTER_MATE - You missed a faster checkmate with 58... Rb6}
({BEST MOVE (+Mat05)} 58... Rb6 59. Rxb6   $18)
({FASTER_MATE (+Mat04)} 58... Rh6 59. c8=Q Rh8+ 60. Kc7 Rxc8+   $18)
59. Ra4+ {(+Mat09)}  Kb6 {(+Mat08)}
60. Re4 {(+Mat08)}  Rh8+ {(+Mat07)}
61. Be8 {(+Mat07)}  Kc5 {(+Mat03) FASTER_MATE - You missed a faster checkmate with 61... Rxe8+}
({BEST MOVE (+Mat06)} 61... Rxe8+   $18)
({FASTER_MATE (+Mat03)} 61... Kc5 62. c8=Q+ Kb6 63. Qc7+ Ka6 64. Ra4#   $18)
62. c8=Q+ {(+Mat03)}  Kb6 {(+Mat02)}
63. Rb4+ {(+Mat03)}  Ka5 {(+Mat02)}
64. Qc5+ {(+Mat02) WHITE WINS - Play might have continued...}
({CONTINUATION (+Mat02)} 64. Qc5+ Ka6 65. Qb6#   $18)
1-0

I just posted the PGN file. I hope you guys can take my game apart and teach me a lesson I will not forget!

Put it in the diagram!

I don't see the hanging rook .

Okay, to answer your original question: Yes, the computer analysis is flawed for 12. .... exd4. As you quite rightly say, this sequence allows 20. Ra8+, winning. White's twentieth move appears to be over its horizon, when calculating from Black's twelfth move.

That's not to say that 12. .... exd4 isn't the best move (as pointed out by a few here), just for different reasons than the rather limited, free site analysis-tool reckons.

Look carefully in the computer analysis, sideline in blue script.

It's here (first blue script after the focus):

 Hmm... the problem is the tactic that it allows. I get it now!

Precisely, it calculates something like 15 ply, anything after that is over the horizon. It wouldn't have any idea if the 16th ply is mate in 1.

Thanks PrawnEatsPrawn.

So should we trust all the suggested moves except the last one ?

That was a damn sexy and artistic blue arrow PrawnEatsPrawn.

;P

 Archaic71, behave yourself please.

It's not that simple, the previous moves lead up to the last one (all part of the computer's plan, as it were). I wouldn't trust any analysis that doesn't end quickly with a concrete advantage or an easily understood plan. Any line that drifts on the full 15 ply must be scrutinised (as you did).