e4 e5
Nc3 Nc6
f4 exf4
Nf3 Be7
Since the knight is already present on the f3 square, black does not have an opportunity to get his queen out now. So the next idea is to get the bishop out and guard with queen in order to attack the weak f2 square. As white player, you should be ready play with a pawn loss for center control and piece developments.
1.e4 e5 2.Nc3 Nc6 3.f4 exf4 4.Nf3 Be7 5.Bc4 Bh4+ 6.g3 fxg3 7.0-0 Nh6 8.d4 d6 9.Bxh6 gxh6 10.Bxf7+ Kxf7 11.Nxh4+ Kg7 12.hxg3 Qg5 13.Qd3 Rg8 14.Nd5 Kh8 15.Kh2 Be6 16.c3 Rae8 17.Rf3 Bxd5 18.exd5 Ne7 19.Raf1 Ng6 20.Nxg6+ hxg6 21.c4 Re7 22.Kg2 Rge8 23.Rf8+ Rxf8 24.Rxf8+ Kg7 25.Rf4 Rf7 26.Rxf7+ Kxf7 27.Qe4 Qf5 28.Qe2 Qf6 29.Qe4 h5 30.b3 Qf5 31.Qe3 g5 32.Qe2 g4 33.Qe3
After white makes the simple mistake black is able to grab the a2 pawn and will be able to comfortably get back to the defense with continuous checks.
Qc2+ 34.Qf2+ Qxf2+ 35.Kxf2 Kg6 36.Ke3 Kg5 37.Kf2 h4 38.gxh4+ Kxh4 39.Kg2 b6 40.b4 g3 41.c5 Kg4
And the king and pawn endgame is lost for white.
In the Cunningham defense, white can either go for a pawn sacrifice or loose the castling rights by moving the king, and thereby seemingly dangerous to be played as white player. These kinds of aggressive setups can be implemented in bullet and blitz games.
