I play this opening frequently in live chess and consider 2. ... Qh4 to be a beginner's oversight (when that move should be reserved if white forgets to bring out Kf3). However, after viewing the orignal game in question and Scarblac's comments, I think that move is fine if played like billsol. I think billsol's problem in the original game was his castling queenside, at least when he did it. But even that could have been fine until move 21 or so when he moved his Knight instead of capturing a loose pawn and activating his rook.
I consider the gambit to be less than middling in theory, but it makes up for it in live play because its infrequency of play challenges black and allows for more tactical advantage than more common openings. Personally, I love that it tends to open up the f-file.
If you don't play e4 e5 then you don't need to know anything about the KG, no matter how high your rating. I play the French defense (e4 e6) and have never had to learn the KG, although my rating is over 2000. I do want to learn the KG because it looks attacking and fun and would be a good complement to my recent repertoire addition of Bird's Opening (1.f4). I know of a 2200+ player who regularly uses the KG to good effect.
Don't write off these slightly different openings - it's all about learning how to play them well. There's more to life than the sicilian and ruy lopez!
It is fun! That's part of the whole point!! I just can't help myself in fact - as soon as I see 1. ... e5 I have a hard time forcing myself to play anything else but 2. f4!?
There are so many winning lines with it, that I remain convinced to this day that there is a way to force a win with it EVERY time. In the other thread mentioned, we are exploring the best defences to it, and the best counters to those defences! It may take a long time (as it already has!), but I'm sure that when it's over, I will have the first 10-15 moves of every KG game possible completely covered, meaning that I will be able to capitalize on it every time and make winning plays!...
I've been at it for a while, but I feel that I am now much closer. And if nothing else, it has made for some amazing games and LOTS of fun in the process!
I'll enjoy it while it lasts, as one day I fear no oponent will dare play 1. ... e5 to the e4 opening, in light of the KG.
Ambitious perhaps, but a dream worth investigating...