By provoking c2-c3 Black leaves the enemy knight without its desired destiny.

Too materialistic.
White should have returned the pawn by 4.b3 Bxe2 5.Rxe2 Qxc3 just yields Black a minimal edge.

Now the active bishop pair more than compensates for the pawn, whereas White keeps having a problem with his misplaced knight.

This attack on the knight forces a minor concession from the opponent.

Accepting some minor weaknesses on e6 and e5.

5...Nxd4 6.exd4 Nd7 7.d5 Nf6 8.Bb3 Kf7 would be better.

Freeing the e4-square for the knight. The game continued:

Black resigned in view of 15...Bxb6 16.Ba4+ Kd8 17.Nf7#

Heading for the protected square at h4 and taking control of the whole h4-d8 diagonal.