In addition to agreeing with most of Uberdude's comments -at least those that I understand - I found move 62 disconcerting.
You have three potential targets: his upper left group, his lower left group, and the white stone at C10.
You have two possible weaknesses of your own: your upper left group ( which has miai north and south), and your pincered stone at C8.
You are ahead in targets, and you have sente. This should favor you. Yet you chose a move that forces him to make himself stronger.
D8 feels wrong here. It releases tension and shuts down future possibilities when you - being the attacker - want to keep all options open and maximize the number of things that he has to worry about.
Someday you might want to attach at D6 or B6, or play B7.
I would have played E8. I can't claim that it is the best move, but it looks theoretically better.
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My only disagreement with Uberdude is that he didn't criticize D12 strongly enough. ( You said 'ruthless'.
)
Your upper left group was moderately safe because it had miai along the left side. He took one, so you must take the other.
When I first saw it, I was wondering why you gave up on playing solidly. The strategy seems to have worked well enough so far, it is time to double down on it.
C12 looks best.
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Move 75 at D18 can't be right. You are attacking from a position of weakness. You have to strengthen yourself first. ( "Make fist, then strike", the Japanese say. )
Again, C12 probably works, maybe E14 also.
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In summary, you have two bad habits exemplified on at least two occasions each:
1) Twice - moves 29 and 67 - you have groups that were safe because of miai. Then he took one and you did not take the other.
It almost looks like you read the joseki book that said "this position is safe, so tenuki is best" without understanding why it was safe.
2) Twice - moves 31 and 75 - you attacked without making your attacking groups strong enough first.