Revealing mistake: In the scene where O'Neil is fighting Ra's bodyguard, the bodyguard uses claws and hits O'Neil's back, tearing his shirt and wounding him. But you can see Kurt's "wounds" and torn shirt right before he's hit by the bodyguard (a scene after Ra's bodyguard's claws are shown). (01:49:10)
Revealing mistake: When the crew is transported to the distant planet, there are three moons. They are all the same shot of our moon (the craters are the same), but each moon is turned differently than the other two. (00:33:15)
Revealing mistake: Right after O'Neil and Jackson are captured inside the pyramid and taken aboard the alien ship a distant shot is shown of the ship while it is opening. In the sky over the ship are depictions of three moons. Each of the three moons shown in the sky of the distant planet are actually the Earth's moon when it is full but just shown rotated slightly in different positions. (01:38:00)
Revealing mistake: On the first night at the slaves' fortress, Daniel is eating the "chicken" and telling them how good it is. After that they take him away to give him a wash. As they walk off, they pass the small fire the slaves have made. If you look at the fire closely, there is a metal circle at the bottom and the fire is coming out of seven holes in it, which means that it is a prop gas fire.
Revealing mistake: When James Spader is first exiting the pyramid after he first arrives on the planet, he begins to touch the wall on the left as the moves out the doorway. He appears to be using the wall for balance. During the last shot before he walks completely out into the open, the "solid rock" wall bends inward like it's made of rubber.
Chosen answer: When Ra saw the bomb, he realised that it was a few seconds away from detonation. There wouldn't have been enough time to send it back.