Chess Game - Control Of Center

I have just finsihed playing this InstantChess game. Any thoughts appreciated. I was white, and  won.

6.Nh5? - This doesn't make much sense... complete your development before attacking. 

6...Qc5? - This makes even less sense, for the same reason.  You plan to attack with 2 pieces and your opponent plans to attack with 1 piece. That gives you an advantage, but beware opponents who know how to use all their pieces!

7.Qh5+ Kd8! - "Pawn move would be better?" - If 7...g6 8.Nxg6! He can't play 8...hxg6 due to 9.Qxh8!. If you didn't see this, then Qh5+ was a mistake. Because after 7...g6 (without 8.Nxg6!) White's queen must retreat.

9...Ke8?? and 11...Kf7?? - Defending is often harder than attacking. His blunders give you an opportunity to win, and you seize it! 9...Bf6 would have held his position together and kept him in the game. Nice winning technique.

Have seen ever seen Morphy's games? He's a well-known American player from the Romantic era of chess and he scored some lightning-fast wins... but somehow he managed to bring all or most of his pieces into the action.

The above game looks interesting.

Continue developing before attacking? Surely, if I see a weakness then I should try and attack that weakness.

He should have also moved his pawn to counter my first Queen check. This would have made my queen retreat, and kept him in the Game.

Isn't it better to lose pieces and win, than keep them all and lose? 

Continue developing before attacking? 

Yes, developing before attacking would make you a stronger player.
 

Surely, if I see a weakness then I should try and attack that weakness.

Not unless you spot a tactical sequence that forces an advantage. In most other cases, developing your pieces and then attacking will win you more games. 6.Nh4?! didn't develop and didn't force the win of material. 7.Qh5 was also not so good since you believed it could be countered by 7...g6.

He should have also moved his pawn to counter my first Queen check. This would have made my queen retreat, and kept him in the Game. 

Take a deeper look. 7...Kd8! was the best move and kept him in the game. If 7...g6? 8.Nxg6!. Then your Queen would have no reason to retreat.