The Blackburne-Shilling Gambit

The Blackburne-Shilling Gambit is a slightly unorthodox line emerging from the Italian. After 1. e4 e5 2. Nf3 Nc6 3. Bc4 there are a multitude of decent moves for Black, the two most popular being 3...Bc5 (Giuoco Piano) and 3...Nf6 (two knights defense).

However, black will go for an interesting choice, namely 3...Nd4!?
Now the best move for white is to play Nxd4 or c3, after which he/she will obtain a pleasant position with a slight opening advantage due to superior development. However, the most critical line is Nxe5, which is a critical mistake.

Black will now play Qg5!, attacking both the knight on e5 and the pawn on g2. The best move for white is Bxf7+ and accept the reality of getting two pawns for the lost piece. While this is a material deficit the compensation is sufficient for some play and white is only slightly worse.

However, the alternative Nxf7?? is a fatal forder (fork + blunder) and immediately throws the game away. Black will play Qxg2, hitting the rook and the pawn. I have included two lines to show how destructive this is (refer to the study posted in the beginning), but I will briefly go over them.

If Rf1, the only way to save the rook, then after Qxe4 Qe2 is forced, losing the queen. If Bxe2 Nf3# is a smothered pin mate.
If Nxh8, after Qxh1 Bf1 Qe4+ Be2 Nxc2 black is winning all sorts of material and is completely winning here.

Refer to the embedded study which has all the required lines. Hope this has been helpful!