I'm afraid I didn't enjoy this much - Although I liked my COD 9a. Otherwise, although it was certainly taxing I found it a bit joyless.
I agree that the reverse is true of 23a and I can't parse 21d even though the answer is clear from the crossers & confirmed by previous comments about the singer-songwriter.
Another gripe is that I wouldn't describe the film mentioned in 1a as a war film...
Also def of 6a is to surely to immitate rather than plagiarise?
Moan over!