Probably laughed more the second time as it's so jammed with treats I missed a few the first time around.
I can understand some of the hate from the very high level of "New Zealand-ness" of the film.
Crumpy? Burger Rings? L&P?
You need an interpreter from the 1980s as well to help with some of the gags.
However if you're New Zealander and from the 80s (all the best people are), this is treat.
I'm not either of those and still belly laughed out loud, although as a Brit from the 80s I suppose the slang (guts for garters) was all recognisable.
"Are you hungry? Wait, look at you. Of course you are!" - you'd never hear un-pc stuff like that in 99% of films today. People just can't wait to be offended, even when the 'offender' is actually poking fun at themselves. I thought the humour was great; very unexpected. Sam Neil saying "S41t just got real" had me in stitches, brilliant.