Something Odd in the Vienna
Your first reaction is probably that Black has no idea what he's doing, and in the game that was more or less true: Black was a very inexperienced player and lost in a hurry: 4.d3 d6 5.Bxh6 gxh6 6.Qh5 O-O? 7.Qxh6 Be6 8.Nf3! Bxc4 9.Ng5 and Black resigned.
While my student was showing me the game, my first thought was one that might have struck you too: Black should try 6...Qf6. Now if 7.Nf3, c6 eliminates any immediate danger, so 7.Nd5 is the only real try. Now things get FUN.
[Warning: the following was just my spur-of-the-moment analysis, sans computer, sans careful double-checking; just me riffing. This for entertainment value only, and to inspire the reader to investigate the material further; computer-generated refutations you may keep to yourselves, at least for now!]
So: 7.Nd5 Qxf2+ 8.Kd1 and now Black seems to have at least two good moves:
(A) 8...Qf1+ 9.Kd2 Qxa1 and now White has three tries, all of which seem to me inadequate:
(1) 10.Nxc7+ Kd8 11.Qxf7 Bb4+
(2) 10.Ne2 Qxh1 11.Nxc7+ Kd8 12.Qxf7 Qxg2 and now, whether White plays 13.Nxa8 or 13.Nd5, Black plays 13...Qg5+ 14.Kc3 Bd7 and wins.
(3) 10.Nf3 Qxh1 11.Nxc7+ Kd8 12.Qxf7 Qxg2+ 13.Kc3 Qg6 wins.
(B) 8...c6 9.Nc7+ Kd8 10.Nxa8 Qxg2 11.Qxf7 Bg4+ 12.Kc1 Nd7 and White is completely lost.
In short, 7.Nd5 looks bad, so earlier improvements are needed. Since Black's playing ...Qf6 turns out to be pretty useful for defensive purposes, the "scholastic" 5.Qf3 quickly came to mind. 5...Qf6?? loses to 6.Qxf6 gxf6 7.Bxh6, and some other ways of defending against the threat of 6.Bxh6 followed by 7.Qxf7# fail quite easily, too: 5...Be6? 6.Bxe6 fxe6 7.Bxh6 gxh6 8.Qh5+ and 9.Qxh6; 5...Bg4? 6.Qg3 (threatening to take on h6 and then on g4) Qd7 7.h3 wins.
That leaves the surprising, bold 5...O-O. 6.Bxh6 gxh6 goes nowhere: the Black queen can easily defend the h-pawn with ...Qf6 or ...Qg5 if need be, while Black can even play aggressively on the kingside with ...Kh8 followed by ...f5. With that in mind, I thought White could combine prophylaxis with aggression: 6.h3 Kh8 7.g4, but now comes my favorite part of the analysis: 7...f5!? 8.gxf5 (8.Bxh6 fxg4!) Nxf5 9.exf5 Rxf5 10.Qe4 Bxf2+ 11.Ke2 (11.Kd1 probably improves, but 11.Ke2 doesn't initially look too terribly risky, while it comes with the added virtue of making it easier for the Ra1 to come into the game) Nc6 12.Nf3
and now Black goes 19th century on White with 12...Rxf3! 13.Kxf3 Bf5! 14.Qd5 Qh4 (threatening ...Nd4+, ...Qg3+ and ...Rf8) 15.Ne2 Rf8 16.Kg2 Nd4! 17.Nxd4 Bxh3+! 18.Rxh3 Qg4+ 19.Kf1 Qd1+ 20.Kg2 Qg1#
Wasn't that cool? I recommend to all my readers that they do their best to analyze the above, (without using a chess engine) - working on positions like these is a great way to improve one's tactical abilities. Better still, it's fun!