Black has a great counterattack in the Gunderam defense, starting after 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Nxf3 Bf5 6.Ne5 e6 7.g4 Ne4!
White has nothing other than accepting black's counterattack with 8.gxf5 Qh4+ 9.Ke2
Now we all know that 9...Qf2+ is insufficient after 10.Kd3 Nc5 11.Kc4 (++). Also, 9...f6 allows for 10.Nf3 Qf2+ 11.Kd3 Nc5+ 12.Kc4 (+)
That brings us to the only black ninth move that is not simply loosing : 9...Nc6. Black has a great double attack lateron.
9...Nc6 10.Nxc6 Nxc3 11.bxc3 Qe4+
The "pointe" of the black attack – a great triple attack.
12.Kf2 Qxh1 13.Na5
The starting point of our analysis. White has a bishop and knight for the rook and a pawn. In addition, white's pawns on f5 and h2 are loose. But white can emerge with a small advantage after careful play.
a/ 13...Qxh2+ 14.Bg2
...a1/ 14...Qh4+ 15.Kf1 (+=)
...a2/ 14...Bd6 15.Nxb7 (+=)
...a3/ 14...Be7 15.Qh1 (+=)
...a4/ 14...Rb8 15.Qh1 (+=)
b/ 13...000 14.fxe6 fxe6 15.Qf3 Qxf3 16.Kxf3 (+=)
c/ 13...Qd5 14.Nc4
...c1/ 14...Qxf5+ 15.Kg1 (+=)
...c2/ 14...Bd6 15.Nxd6+ (+=)
...c3/ 14...Be7 15.Qf3 (+=)
...c4/ 14...000 15.fxe6 (+)
Now it seems to me that the majority of these positions is quite unclear to me, even if Houdini gives white a small advantage. But white surely has to play decent chess as to deal with black's material advantage. White's advantage lies in the exposed position of the black queen, but still, the material imbalance ( rook against two pieces ) leads to a difficult game for both players.
Still, it is black who took the initiative and dictates the game from move 7 onwards - a feeling most gambiteers will not like that much.