?! Doesn't seem bad, but allows the pin ...Bb4; I like Nf3 in this position, since ...Bg4 h3 Bxf3 Qxf3 points at the f7-pawn and leads in development, and ...Bg4 h3 Bh5 lets White play Qd1-d3, Bc1-Bd2 or Bc1-Be3, and O-O-O, with a decent position.
4... Bf8b4 5. Bc1d2
Is Qd3 an improvement? Protects c3 and d4, clears the way for Bd2 and O-O-O. Furthermore, Bd2 allows Black to play ...Nf6 without the waste of a tempo on ...h6.
5... Ng8f6 6. Bf1d3
?! Neglects the threat to the d4 pawn. Nf3 or Ne2 may have been better.
6... O-O
?! Was an immediate ...Nc6 better? Creates the threat of Re8+, but Knights-before-Bishops-before-Rooks, as some old dead guy said.
7. Ng1f3
? The cramped Ne2 had to have been better. Now there are duel threats of ...Bg4 and Re8+ on the horizon, and they can't both be stopped.
7... Nb8c6 8. O-O Bc8g4
! Black has an intimidating symmetry, and white is cramped. d4 is looking weak. The threat is ...Bxf3 Qxf3 Nxd4.