1.e4 e5 2.Nf3 Nf6 3.Nc3 Bb4 4.Bc4 d6 is completely fine for black. Later he will castle, maybe Bxc3, Be6 to trade bishops, with an equal game.
4...0-0 should be fine too- 4...d6 just makes trading the bishop for the c3 knight unnecessary.
more people should look at the line imo...too often i play weaker players who try to be a bit too hypermodern and then wind up handing me all the advantages of the halloween gambit without me having to sac at all lol
Oh yes when I was still a beginnier I would always fianchetto my bishop and give my opponent space and randomly trade pieces for no reason because I thought it's a good idea.
I want to make sure everyone understands lol.
I am only joking about the Halloween Gambit lol
Hopefully, You do not take what I say about it way to seriously. I figured some would get the joke.
Yeah it is fun continuation.