Was just trying some unorthodox, and probably annoying tactics.  Isn't the initial part of the opening known as Alekhine or ?

The book move after 1.e4 Nf6 2.e5 Nd5 3.d4 d6 is 4.c4, by playing 4.f4 you allowed Black to liquidate your central pawn mass after  4...dxe5 5.dxe5 now the pawn structure is symmetrical and drawish (same number of pawns on kingside and queenside divided by the open d-file).  You do have some initiative to establish a bind on the kingside but Black can castle on the queendside.  In the endgame a quartgrip is possible on the kingside with the white pawns on e5,f4,g4,h5 and Black pawns on e6,f7,g7,h6. This makes it possible for you to get a passer with a well known endgame technique.  You can look it up if you want.