Softening up White's pawn majority and freeing the d5-square for the knight.

Preventing ...b5-b4, but also leaving the queenside structure in a bad shape.

3.Ne5 would be better.

After some consolidating moves Black is ready to fight for the initiative by ...Nbd5 or ...Nc4.

This loses a piece.

10.Nf3 Rc4! Trapping the queen.

Black soon won.

Softening up the d5-square for the knight.

1...exf5 2.exf5 g5 3.Bg3 +/-
1...e5 2.Ne6! Nxe6 3.fxe6 Rxe6 4.Nd5 , followed by Bg4, leads to an even bigger advantage

Now Black will never be able to recover the pawn; but after 4...Nxe4 5.Nxe4 Bxe4 6.Qh6! White would have a strong attack.