The Hanoi night Market is extremely busy! So many people! Other reviewers have suggested that it is s Fri, Sat and Sun night affair only - so worth coming on one of these days.
A District of the old town is coroned off to all but foot traffic, which makes the area around the night Market a chaos of pedestrians, cars and motorcycles all coming to - or trying to bypass - the market.
Recommend you go to the what is now the Old Town Restaurant and Pub and watching from the balcony aa another reviewer helpfully suggests.