1.d4 d5 2.e4!?
1.d4 d5 2.e4!? loool...what a strange move! 2...dxe4 that's the main line. 2...e6 that is french defense and 2...c6 is karo-kan defense.. After 2...dxe4 3.Nc3 Nf6 4.f3 (4.Bg5 is also possible) 4...exf3 5.Nxf3 and now if 5...Bg4 White can play ...