Chess Opening: English Four Knights' 4.g3 Nd4!?

In this video I explore a gambit line for Black in the Four Knight's English: 1.c4 e5 2.Nc3 Nf6 3.Nf3 Nc6 4.g3 Nd4!? I found this idea in the book Starting Out: The English, by Neil McDonald. He spends one sentence dismissing White's acceptance of the gambit with 5.Nxe5. Being curious, I launch an exploration into this line... Black gets good attacking chances in all lines, but it's by no means a forced win. Especially after the best defense 8.Kf2, Black has some work to do. I ran short of time so this video doesn't really have a conclusion. Basically, White can survive, but Black has enough long-term compensation for his pawn.