It's in the trailer and the actual premise of the movie so not spoiling. Why if the future people can travel back in time, don't they just do what Andy Dwyer ends up doing and just track down the aliens and kill them before the war starts? That's a huge plot problem that the movie doesn't even attempt to address. AlsoSpoiler: Showwhy all the emphasis on the toxin when in the end they just kill the aliens by blowing them up and kicking them really hard near the edge of cliffs.
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