boxing my bishop in, taking the support from the knight. Nicely done.

I did consider exd4 as well but my king remains very exposed and Re1+ could've led to a checkmate as the e6 square is weak.

? Why not simply gxh3 ?

Blatsting open the route for the bishop while keeping the e-file closed, as the white king's knight can't capture due to the threat Rxf1 checkmate.

? Why not cxd4?

Taking out the white king's best defender, adding a threat at Nf2+ and opening the diagonal for the bishop.

crucial but too late.

Opens the route for the rest of the dark forces to come to play. Not the best way to do it though.

There are more urgent things to do - bringing the bishop and the rook to the play. Ne4 maybe?

blocks counterplay, continues attacking