I thought the explanation of how the Blight was going to render Earth's atmosphere unbreathable was sort of unbelievable. The Blight's metabolism excretes or produces nitrogen gas at such a high rate that the percentages of the atmosphere's constituent elements are going to change drastically within a single generation? (c.f. the scientist saying that the last people to starve would be the first to suffocate.) Is that even possible? I mean, we burn fossil fuels and emit CO2 like the dickens, but nobody is arguing that we're going to die of CO2 poisoning instead of being threatened by global warming.

Also, near the beginning, the ersatz Predator was supposedly solar powered (hence being in the air autonomously for ten years), but when it lands it's just a metal plane.