How to Use a gambit in the English four knights chess opening

In this video, Matt explores a gambit line for Black in the Four Knight's English: 1.c4 e5 2.Nc3 Nf6 3.Nf3 Nc6 4.g3 Nd4!?

He 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, Matt launches 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.