Tom Sermanni's team were beaten 1-0 by the Netherlands and 2-0 by Canada in their two matches so far, with the New Zealanders constantly on the back foot and chasing the ball.
Even in rare periods of possession they were pressed high up the pitch by Canada and saw their midfield and defence come under pressure.
The Canadians registered 22 shots, while New Zealand had just two.
"When you do that sort of running defensively, it makes it very hard to attack," said Longo, who replaced the injured CJ Bott after 18 minutes in Grenoble.
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"The movement off the ball is a little bit slower, which means they can get around the ball and crowd it.
"So one of our key work-ons is going to be keeping the ball and you need the ball to score goals."
New Zealand have qualified for four previous World Cups but never advanced out of their group and the team had set that as a minimum goal for the tournament in France.
Cameroon, beaten 1-0 by Canada and 3-1 by the Netherlands, were an "unorthodox side," Longo said.
"We didn't know too much about them but we've had two games to see them play at this World Cup and they look like a very good side with a number of quick players.
"Sometimes they're a bit unorthodox in the way they play which can be difficult to play against.
"So we'll work really hard on that in training and make sure were ready to go."
(Reporting by Greg Stutchbury; Editing by Peter Rutherford)
