
must block. No questions. The move is aji-keshi at best.

again must block.

again must block. BLack finally punishes with

I believe the double hane works. You could also consider hane at O4. The earlier joseki choice is not good by white, however, and black's response was terrible. After

however, black has the advantage by far. Regarding the joseki choice, white is emphasizing the direction that black has influence in, so it isn't as big as emphasizing the direction white has influence in (the bottom).

too close. Just approach the corner.

This 3-space keima is not good from the corner in general. Normally, it's either too far or not far enough: It doesn't much protect the corner, but if you're not going to protect the corner, you should extend farther to not be overconcentrated.

this feels painful. White has already lost his territory... just tenuki if you won't fight back.

is very slow, but

is terrible. It's a dead stone, so just let black take it on a small scale. Running with it means that white has a group with no purpose (not cutting black or anything) that is getting heavier and heavier.
The sequence on the top through

or so is black taking advantage of the weaknesses white left behind earlier. It's not the most advantageous way but it works.

I know the game is going poorly at this point, but you can't just ignore this.
In sum, there are a few big and recurring problems, not all of which I pointed out specific moves for:
- Allowing your shape to be broken without compensation
- Placing value on worthless stones
- Following the opponent
- Not paying attention to weaknesses and strengths of groups
- Playing too early on the 2nd line
I don't think that black played above his level, but white never challenged any of black's frequently questionable moves, and made early strategic choices that left white in a poor global position.
(edited for formatting)