interesting gambit idea, what's its name?

It's called the Diemer-Duhm Gambit :)

Diemer did have some nasty ideas in the opening. Great presentation! I loved the 3rd move, and the exchange sacrifice on f6 for a longish attack. One variation I liked was after Re1, if black tried ...f4, there is suddenly Ng4. 

3... c5 doesn't look like a very serious move, in view of black's lack of development. Shouldn't it be just enough to go 4. dxc5? Even a Q exchange doesn't defend the e4 pawn and white is just better and with a nice and open game.

Solskytz good point if 16...f4 17.Ng4! ends it :)

if 3...c5 4.dxc5,Qxd1 5.Rxd1 Bxc5 5.Nxe4 Be7 (of course if 5...Nxe4 6.Rd8++) and white has a small edge

another move against 3...c5 would be 4.d5 and white can regroup in the center with a passed d-pawn...

Isn't that funny? Following your brilliant article and my own brief analysis of options coming therefrom, watch this cute little crush of a near-2000 blitz rating guy here - and this in five minutes chess (rather than the three I usually play):

heheee! nice! glad it worked! and he fell in the line we talked about! :)

Quite amazing... to get to talk about a line one day, and then trap a hapless opponent on the next...

Although - later an opponent played a line which rather embarrassed me. Houdini also gives him the advantage... maybe you have an answer to that? Check it out:

Hey solskytz, after 6...fxe4 you can play 7.Bg5, Be7 8.Qa4+, Bd7 9. Qb3, Bc6 10. 0-0-0 and you have some tactical opportunities with d5... you don't have to worry about his e-pawns because it's a matter of time before you collect them :) hope you get to try this line again some day :)

Sounds pretty exciting... gotta try that some time :-)