The normal route is 1. e4 e6 2. d4 d5 3. c4 dxe4 4. Nc3 Nf6 5. f3.
5... c5 6. d5 exd5 7. cxd5 exf3 8. Nxf3 Bd6
This is the most quoted DDG variation. Black has clear advantage according to Keres.
9. Bb5+
I have tried 9. Bd3 with no success.
9... Nbd7
This is not yet the crucial mistake, but 9... Bd7 10. O-O O-O is much better.
10. O-O O-O 11. Bg5
11. Ne4 hxg5 12. Nxd6 Qb6 13. Nf5!? Qxb5 14. Ne7+ Kh8 15. Nxg5 with the threat Rf3 would be very wild. Worse is 13. Bxd7 Qxd6 14. Bxc8 Raxc8 15. Nxg5 Qxd5 -/+.
11... h6 12. Bh4 Re8
This naturally tries to prevent Ne4, but now both Black knights are pinned! 12... a6? 13. Bxd7 Bxd7 14. Ne4 +/=, but 12... Qc7 13. Bxd7 Nxd7 14. Nb5 Qb6 15. Nxd6 Qxd6 =/+.
13. Nd2!? g5
13... Be5?! 14. Nde4 Qb6 (14... Bxc3 15. Nxc3 Qb6 16. Bxf6) 15. Bxf6 Bxf6 16. Nxf6+ gxf6 (16... Nxf6 17. Rxf6!) 17. Qg4+ and 18. Bxd7 wins a piece.
14. Nc4 Bf8
15. Qf3!!
Now Rebel's assessment of the game dramatically jumped when it realized that White left a piece en prise. The consequences, however, are impossible to calculate precisely. So is this a tactical or strategical (positional) sacrifice?
15... gxh4
A piece is too tempting. 15... Bg7 16. Bg3 a6 17. Bxd7 Bxd7 =.
16. Bxd7 Nxd7
Some human players would probably have preferred the bishops vs. knights middlegame after 16... Bxd7 17. Qxf6 Qxf6 18. Rxf6 Bg7 (18... Kg7 19. Raf1) 19. Rf4 h3 20. Nd6!, which is unclear. White seems to regain the pawn, but Black should have some advantage even though the pawn structure is a mess.
17. Qxf7+ Kh8 18. d6
Fritz 3 managed to analyse Black to death as follows: 18. Qg6 Re7 19. d6 Rg7 20. Qxh6+ Rh7 21. Qf4 b6 22. Ne5 Ba6? (probably the losing move of this variation; 22... Nxe5 wins easily) 23. Ng6+ Kg8 24. Rf3 Rc8 (24... Bb7 25. Qc4+) 25. Qa4 Rg7? 26. Ne7+ Bxe7 27. dxe7 Qxe7 28. Qxa6 +/=. Moreover, Genius 2 found 25. Qg4! Rg7 26. Qh5 Rh7 27. Qd5+ winning.
Anyway, this is a terrific game for analysis. Genius 2 repeatedly thought that Black was clearly better, about two pawns up, but after two or three moves, White suddenly was winning.
18... Bg7
Black is running out of moves. Black's queen's rook and bishop are totally useless, and other pieces have very little space, too, so the position is well worth a piece. 18... Ne5? 19. Nxe5 Rxe5 20. Qxf8+ Qxf8 21. Rxf8+ Kg7 22. d7!.
19. Nd5 h3
Computers are known for finding good defending moves, but now it is complete waste of time to move the h-pawn -- and even twice.
20. Ne7 hxg2
Simply better is 20... Bd4+ 21. Kh1 hxg2+.
21. Rf5 Rb8?
The last mistake. 21... Rg8 keeps the clear (winning) advantage.
22. Re1
22. Rh5 seems to work as well.
22... Rg8
23. Re6
White seems to have plenty of choices:
23... Nf6
23... Bd4+ 24. Ne3 Bxe3+ 25. Rxe3 Rg7 (25... Qf8 26. Ng6+ Rxg6 27. Qxg6 mates quickly) 26. Qh5 wins.
24. Rfxf6 Bxe6 25. Qxe6 Bxf6
25... Kh7 26. Qf5+ mates.
26. Qxf6+ Kh7
26... Rg7 27. Qxh6+ Rh7 28. Qf6+ Rg7 29. Ne5 wins the queen, so Rebel first thought that White has perpetual check...
27. Qf5+ Kh8 28. Ne5 Qe8
But soon Rebel had to admit that the game is over: 28... Rg7 29. Nf7+ Rxf7 30. Qxf7 Qxd6 31. Ng6+ wins the queen.
29. Nf7+ Qxf7
29... Kg7 30. Qg6+ Kf8 31. Qxg8# would be too claustrophobic.
30. Qxf7 Rg7 31. Qf6 Kh7 32. Nf5 Rg4 33. d7 Ra8 34. Qxh6+ Kg8 35. Qe6+ Kh8 36. d8R+
A quicker win is 36. Qe8+ Rxe8 (36... Rg8 37. Qh5#) 37. dxe8Q+ Kh7 38. Qh5+.
36... Rxd8 37. Qf6+ Kh7 38. Qxd8 1-0