4 game match- opening errors

http://www.chess.com/livechess/game?id=1322543857

http://www.chess.com/livechess/game?id=1322553201

http://www.chess.com/livechess/game?id=1322554656

http://www.chess.com/livechess/game?id=1322564113

Please help me understand the mistakes.

In game 3, I messed up his rating and spelling LOL!

Please! I need help! Especially for the line in game 3.

Game 2, you might have considered 8. O-O

Thanks, what about the 3rd game? Even if the opening was fine I messed up the middlegame. See the link.

Also, what could he have done in Game 4? I just saw Qh4+

How do you recommend I protect my pawn? 

Nbd2 threatens e4.

Or do you recommend I exchange?

Ok, I'll keep that in mind, thanks.

What about Game 3 and 4?

What was white's alternative to d5?

EDIT: Could he play Nf3

Please help...

Thanks, any advice?

Somebody please assist with G4

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