Trap In Vienna Game

This is the Frankenstein Dracula Variation. Black has good compensation for the material loss. It's very hard to play the White side of this. You'd better be booked up if you want to play like this. (Here is a famous game for example: http://www.chessgames.com/perl/chessgame?gid=1102845 )

I don't see a trap, i just see a blunder from black on a tricky opening...

White's threat being obvious after Nb5, almost everyone should play g6 easily, whatever the level.

Dracula Frankenstein is a scary opening (thus its name), it may be unsound but if black wants mess...

If black wants a simple approach, then 5...Be7 followed by castle does the job, with instant equality and maybe more...

I understand this, thank you however, I still believe that this may give black a losing position quickly