This story may not be unique but even with its origins being inspired by other films... it presents it in an unusual way that will catch some by surprise. 

Blurb:

We've seen invasion movies where survival is the name of the game. This one has a slightly different twist as the aliens aren't what you expect. The only hope for survival is at elevation and there doesn't seem to be any way to fight back. Will they find an answer before it's too late? That will answer itself, as well as something in the credits that leads the viewer to imagine that this isn't the end...

Notes:

Red rock settlement,  sugar loaf run, Luck is not a strategy,  cathedral point overlook, Elba fire rd, reaper scale,  Alta Vista ski area, predators kill to eat the reapers kill to kill,   calway mine, they track us like giant mosquitos,  N 780 CO, casein a protein in cheese it's as addictive as morphine,  anger is a terrible thing to waste,  Nina Richmond, Billy Richmond,  I only blame you because it's easier than blaming myself,  N 583 CO, Hamada industries, cobalt,  crows nest,  red rock,  lost gulch,  bonus scene in credits,