== 4...Ne7?? ==
This move cramps Black's position even further and allows Ng5, when f7 cannot be comfortably defended. One example: d5 Qh5 (g6 Qf3 (Nf5 Bxd5) f5 Ne6 wins the queen) Ng6 Bxd5, and Black won't live very long due to f7.
== Theory table ==