Unless it's a metaphor for " Everything wants to kill everything else, including you, and is very fit for it", a planet where "everything has evolved to kill humans" while the humans were absolutely absent from it, makes about as much sense as saying that everything currently on our planet evolved to hunt Neptunians.
Besides which, if such temperature swings were possible, then the trek to the tail would be impossible on account of the massive superstorms rendering the path impassable. Artistic License Physics: A little thing called the greenhouse effect renders wild temperature swings like those seen in the movie impossible.
Archaic Weapon for an Advanced Age: The Ranger Corps prefer to use melee instead of projectile weapons.Anti-True Sight: The alien monsters can detect humans by smelling the pheromones released by fear, Ghosting is a technique in which the subject feels no fear and becomes invisible to the monster.All There in the Manual: In regards to the Backstory of AE's fictional universe.Exactly what happened is explained in supplemental material. After the End: The setting of the film is set a thousand years after humans almost destroyed Earth by environmental mismanagement and were forced to emigrate to another planet, where they encountered a hostile alien species with which they entered into a prolonged war.