White's bishop got trapped on h6 but survived, while black's bishop got trapped on c8 and died.

I was black. This is the most ridiculous game I've ever played. lichess.org/cZkcEkHc

You're welcome to just enjoy the game, but an explanation of what went wrong would be welcome too. I don't understand what went wrong (other than my mistake on move 26). I thought 20...Na6 was a mistake and that I should have played 20...Rxa1, since there were some lines later that I wanted to put a rook on d7, but it runs into the Nb6 fork. However, the computer said 20...Na6 was actually OK.

@theme, In my opinion, Black early removed the tension in the center of the movement f5-f4, which gave White freedom of action on the queenside.

If you can't get an attack going on the kingside as black in the KID then you're toast...white just has all the fun on the queenside.

14.Bf6 was a strategical blunder,you're entire army gets tangled up and you can't get anything going.Better was 14.h6 followed by g5,Nf6,h5,g4 etc.

@CerebralAssassin19 The exchange of bishops is beneficial to Black, so the movement 14. ...Bf6 is not a mistake. But after White rejected the offer of exchange, Black had to play 15. ... Bg7 and further h7-h6, g6-g5 ... although I continue to hold the opinion that with the move f5-f4 it was possible to wait.

7 e4 is a strange move that donates a tempo to black, so it transposes to a king's indian attack with colors reversed.
10...Qe8 unpins the knight, but the queen is not that well on e8. You will return it to d8 later, losing 2 tempi. Better to kick the bishop with 10...h6 like Steinitz propagated.
11...Nfd7 is weird: what is the knight going to do on d7? Going to c5 is impossible as his colleague is already there. I guess you want to prepare 12...f5, but that is not strong with the knight on d7.
16...g5 is wrong here. It is a normal move with the knight on f6, but not with the knight on d7, where it blocks the diagonal of Bc8. The usual ...g4 is no threat here, as neither Nd7 nor Bc8 covers square g4. From here on it goes downhill.
"an explanation of what went wrong would be welcome too" You played too stereotype: you played usual moves in different positions, but not here with Bg5. You had to react better to Bg5; with ...h6! right away, not with the weak Qe8.
Your moves 11...Nfd7, 12...f5, 13...f4, 16...g5 are usual and good in similar positions, but not here with the bishop on g5. The move ...f4 usually attacks a bishop on e3 and shuts it out of the game. 16...g5 only makes sense with the idea of ...g4.

@tpr Yes. Weakened, as a result of movement a7-a5 of the square b4, the black queen bound herself, at least temporarily, with the protection of the pawn c7. This move 10. ...Qe8 is illogical.

Reply to #2 (@ujcn):

f4 is a very common move in similar King's Indian positions, intending to attack white's king with moves like g5 followed by g4. I'm not sure what else should be my plan in this position.

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Reply to #3 (@CerebralAssassin19) and #4 (@ujcn):

I considered h6, too, but ended up deciding against it. I just thought that if white plays Bh6, then I thought that I could eventually win that bishop. I guess I misjudged that.

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Reply to #5 (@tpr):

When I planned Nd7, f5, and f4, I initially intended to follow it up by h6 and g5, gaining some tempi. There are lines where black just plays Nd7, f5, f4, g5 and then Nf6, preparing g4. There are also lines where black plays f4 without attacking a bishop. Note that in lines where black attacks a bishop on e3, the bishop ends up on f2, where it is an important piece both for defending white's king, and for supporting white's c5 advance.

If I didn't play Qe8 and Nfd7, what should I have done? Should I have done something like h6, g5, Ne8, f5, f4, Nf6?

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Reply to #6 (@ujcn):

I've actually seen some lines where black plays Qe8 to unpin the knight, so I don't think Qe8 is obviously illogical. After checking again, though, seems like the usual sequence is h6, Qe8, Nh7, h5, Bh6, and later playing f5. That plan just looks bizarre to me though.

Quote: Reply to # 6 (@ujcn):

In fact, I've seen a few lines where Black plays in Qe8 to unlock the knight, so I do not think Qe8 is clearly illogical.
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After moving 10. ... h6, the white elephant should retreat to the square e3 or square h4. In the first case, the knight f6 is released to go to square d7, in the second - you can continue to reflect the white elephant by the movement g5-g4. Therefore, the problem is solved. If the black queen moves to square e8 in several versions (lines) after the transition of the white knight Nb4, the black queen must return to square d8 to protect the c7-pawn in d8 (e7) or become the square f7, where it is under X -rech rok f1.
If your partner shies away from the usual, you need to think with your head to avoid getting into the worst situation.

"If I didn't play Qe8 and Nfd7, what should I have done? Should I have done something like h6, g5, Ne8, f5, f4, Nf6?"
Instead of 10...Qe8 better 10...h6: kick the bishop right away. If he retreats 11 Bh4, then 11...g5. If he retreats 11 Be3 or Bd2 you can continue your plan of ...Ne8 and ...f5. After 11 Be3 you must protect 11...b6 to keep your centre intact in case he trades Bxc5. Maybe 10...Qe8 is not bad.

Instead of 11...Nfd7 you could have played 11...Bd7, 11...Bg4, 11...c6, 11...Kh8 (intending Ng8 and f5 and Nh6, with double or triple control over f5). Maybe 11...Nfd7 is not bad.

Instead of your 12...f5 you had another opportunity to kick the bishop with 12...f6.

Instead of your 14...Bf6 maybe 14...Nf6 was better. It reopens the diagonal of your good bishop Bc8 not on the colour of your pawns. Even your bad bishop Bg7 on the colour of your pawns is often better that one thinks and often deals a final blow via h4 and g3.

Instead of 15...Rf7 you could have played 15...Bg7, with possible move repetition after 16 Bg5 Bf6. This is proof that your previous inaccuracies were not so bad: you could still go for repetition. Thus the position is still balanced.

Your 16...g5 is a mistake since you cannot follow up with 17...g4 as you do not cover square g4. 16...Na6, 16...Qd8, 16...Bg7 make more sense. Now you stand worse. White develops his initiative on the queen's wing: drives your Nc5 back, advances attacks c7... You have no counterattack on the king's wing. One reason is Bh6, that hinders your motions. The other reason is Nc5, later Na6, that is far from the king's wing. In the usual variations with f7-f5-f4 and g6-g5-g4 that knight is via b8-c6-e7-g6 available on the king's wing.