Given the alternative was to lose more material, it's ok to double up pawns here.

Is it better to be down an extra piece (3 pawn disadvantage) or have doubled isolated pawns (0.3 pawn disadvatage)?

This is a blunder, almost forcing white to put a pawn on g3 and win material! As noted before, the bishop is pinned.

In this instance, the bishop actually isn't pinned at all. As has already been pointed out, Black still had the win of a whole rook at least by 23...Bxh2ch 24.Kxh2 Rxf1, with mate or the win of the c1-Bishop to follow. Having said that, this pawn thrust is not so bad a 'second best' move!

Understandable. But I like 24...Nd4, with the idea 25.gxf4 Qh4, and to threaten mate by 26...Ne2#. If instead 25.Rxf4, ...Ne2ch is still strong.

How does it do that? This does win material, but I can't help look at the queen and rook both at home on their starting squares, contributing nothing to the game. White wouldn't last too long if those two pieces came out.

I like 28...Qf6.

29....Qe7

This isn't a double check

This is a 'discovered check.' The move I like instead is 30...Qh4 with the idea 31.Rf3 Qh1ch 32.Kf2 Qxg2ch 33.Ke3 Qe2#. Mate should follow quickly however White plays.