This is a pretty good game IMO, though like you say it might not be a really high level setting for the Kasparov computer opponent.

I think Black has to play ...Qg6 a move sooner and attack White's f-pawn. After you play 21.Qh6 as white it looks like game over, unless I am missing something. The point is that it takes several moves to prove that 21.Qh6 is winning, so if your computer is not at a setting where it looks five or six moves deep, it might not see that the move 19...c5 is a losing move.