Major General Skyler is wearing a green shirt underneath his BDU blouse, when it should be brown. His BDU blouse is also missing a U.S. flag on the right sleeve and his patrol cap is also missing rank insignia.
The alien weapons are clearly plastic.
At the beginning of the movie we are told that America's share of the 8 million people the Kulku want is 800,000. A news report then says that 650,000 people have already been picked and we're still short 300,000. That means that for some unexplained reason America's share has gone up by an extra 150,000 to 950,000 people.