1.e4 e5 2.Qh5
2…Nc6 3.Bc4 g6
Black can also try developing the bishop along the a3-f8 diagonal, but this is faster. White has a few options, this is the first critical moment for white.
6.Nbc3 d6! is strong, although 6…Na5 is also strong.
The reason behind this is that
7.h3 is not played, the Bishop jumps on g4 attacking and misplacing the queen while developing a Bishop!
7.h3 is played, black has the strong 7…Nb4! 8.Bb3 (8.Be3 is no better) 8…Be6!
9.0-0 (9.Bxe6 fxe6 10.Kd1 and now the king can’t castle and is very uncomfortable)
(9.Ba4+ c6 is very strong, threatening b5, and after 10.a3 a5! Is good for black)
9…Bxb3 10.cxb3 (10.axb3 Nxc2 11.Rb1 and the rook is safe, but the pawn on c2 fell and the doubled isolated b pawns are weak) and white is backwards. The knight eyes d3 as a possible outpost, although there is no way to do that at this point. But this is good for black.