After Nafrayu is killed by Apophis and his father is carrying his body, which should be dead, Nafrayu's head is upright; if he were dead, his head would be limp. And it's not being held up; in fact, it is even jostled and he keeps it up. But if he isn't dead, then they would not need to use their powers to bring him to life.
While SG-1 is formulating the plan to capture Apophis, the amount and pattern of rain on Teal'c's head changes between shots.
At about 41 minutes, when the Nox city first appears, a suspending cable can be seen running horizontally across the screen.