the 1...g6 is like a fortress solid defense

Nah, it's not. 1. e4 g6 2. d4 Bg7 3. Nf3 d6 4. Bc4 Nd7 5. Bxf7+ Kxf7 6. Ng5+ and white wins.
Black gets mated next move or loses his queen.
Nah, it's not. 1. e4 g6 2. d4 Bg7 3. Nf3 d6 4. Bc4 Nd7 5. Bxf7+ Kxf7 6. Ng5+ and white wins.
Black gets mated next move or loses his queen.