It was a disaster. New Line Cinema wanted an up-market shocker, and ended up with a cobbled together montage of ape-suits, shit acting from exploding egos (Brando/Kilmer), and a story with less authenticity than Plan 9 from Outer Space. It was laughed at in cinemas. To be fair, it's watchable, as those low-budget action movies that pad-out the schedules of cable channels can be. And there's money on show with expensive gore and explosions. I've seen comments from people who think it's great. I saw it years ago and thought it was dreadful.
The story is that Brando and Kilmer just fucked about on set like insane, self-indulgent pricks, plus Stanley who created the whole project was replaced by Frankenheimer. The lead actor (Bruce Willis) dropped out before filming, replaced by Rob Morrow (?) who realised he'd landed in a tub of shit and quit, followed by David Thewlis. From what I can see, though, the main problem was the usual chronic interference from the production company.
The book is good. Very strange.
Also, Stanley was contractually obliged to stay away from the set, so he went and lived wild in the outback, existing almost entirely on weed.
When colleagues finally discovered him, they sneaked him back on set as a dog-man, where he stayed as an extra - always in costume - for the last weeks of production. It's an insane story.