1. It's not an opening, it's the 1st move to an opening. 2. There are a few other good 1st moves. 3. Likewise the Sicilian is not the standard defense, there are a few standard defenses: e5, e6, c6 etc..

lol That makes a bit of a mockery of the game of chess to be honest. It should take a lot of effort to win and u here are hoping for the worst possible response!

No, it's clearly a terrible set-up. U just voluntarily pinned your own Knight, not wanting to admit your mistake of 4 Qa5+ and now your position is really vulnerable.

No, this is a good move. Ties up Queen and Bishop and both pieces can't move.

Clearly not. He had u exactly where he wanted u and just relieved u from your agony, for not much reason.

Obviously an oversight. It is said that the kind of moves most often overlooked are retrograde diagonal moves, as here. Though apparently such moves along the long diagonal (also as here) are less likely to be missed than on other diagonals. Still, an easy mistake to make.

What's the threat??

It usually is a good idea to castle, especially as his Queen is still on the board.

?? Walking into a fork. Now 21...Qd3+ does'nt merely pick a rook, but it actually mates. (22.Kg1 Qxb1 and the queen and the knight can just delay the back rank mate) One should always pay special attention to loose pieces!

You should explain where these supposed 'threats' are u keep talking about. I fail to see them.

Really? You don't see Rb3 Rc1 mate? It's the same old tactic of hoping for the worst possible move.

Rc2 surely must be the move to make here, if u don't mind losing the pawn.

meh.. with more simplification it should still be a formality.