Shocking Sicilian Variation...

I'm not an expert in openings, but what do you think of the following variation? I came along that in one of my games.

hmm looks very promising. dunno :P think black has compromised a bit. f5 doesnt look too strong, think Nf6 is better

Two points:

a) White missed 5. c4. That is the reason, why black usually plays 4. - Nf6.

b) The final position is unclear. White can play 9. f3 preventing black e5-e4 and then 0-0, Re1 with pawn up and counterplay. Black's Qb6 is met with Qe2 and Be3 (d4 -> Bf2 and black pawn is still pinned to queen).

I have been seeing this more and more recently.  I refer to it as an "improved Kalashnikov" because white cannot profit from Nd4-b5.

The key move is 5.c4. White usually has a lot of trouble trying to engineer this move against 2...d6 Sicilians; e.g.

- 1.e4 c5 2.Nf3 d6 3.Bb5+ Bd7 4.Bxd7 Qxd7 5.c4 and white had to trade bishops first, which is in black's favour.

- 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Qxd4 Nc6 5.Bb5 Bd7 6.Bxc6 Bxc6 7.c4 and white had to give up the bishop pair.

- 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.f3!? and white can often achieve c4, but black has faster development (and can try for a quick ...e5 and ...d5 to prevent c4).

In your line, white simply gets it for free, no questions asked.

Neither of the seventh moves makes much sense to me.  A Bishop is not a pawn and why play f5 simply to allow exf5 at White's choosing.