I think the hardest thing to do was to get in enough info about the characters so hopefully you'd care about them, without slowing things down too much. That's why you learn stuff later in the novel about some of them, because I didn't feel I could slow down too much before that.
I also had some trouble with the temple night battle scene. It's not very long in the final version, but it still feels too long to me. If I had something to do over, I might refigure that scene. The main problem being--I don't see Gustat or Horia being stupid enough go over to the temple and take on the Predator there. I think in a standard action movie, they'd all go there. But I wanted as much as possible to write a novel where most of the people in it try to act as smart as possible and still mostly come to grief.
I always think in Predator or Aliens books or movies you're doing the fans a disservice if you don't show them something about the Predator or Alien they might not have known before. So I would've liked to get in more stuff like the fact that the Predator uses the 'dreds for balance and kind of like a cat's whiskers. More views of the Predator fighting on other worlds, that kind of thing. But, then, again, you want to keep the story moving.
I noticed some readers had some problems with the alien virus/bacteria that winds up affecting Nikolai so drastically, so I might've messed around with that a bit more. I just liked the idea of the Predator being a sloppy carnivore and bringing in an invasive species from his last kill.
I loved Pol Pot the croc so much I had to resist making him a main character. But I think that was the right decision.