Alien

Looking at Alien is quite something as it might be the most overachieving film of all time. Just in terms of its central idea it’s a monster in a house thriller, but the house just happens to be a spaceship. The film knows no such simplicity, even though the plot itself does technically hold true to that form. The screenplay though isn't simple. I don't just mean that in the twists and turns, which should not be hand waved as the several twists in the film are some of the most effective twists you'll see in any film. It also cares so much for character. Although most of the characters are going to be killed, they are not just there to be killed. We learn about each of them as people, and there is real dynamic across the crew. Of course this is helped greatly by the film having one of the greatest ensembles of all time. There is not a wasted performance everyone adds something extra with how honestly they inhabit their characters in this film. Then there's every technical element of the film all utilized brilliantly by Ridley Scott's masterful direction. His vision takes the film to even greater heights as it crafts this world that is terrifying, awe inspiring, and lived in all at the same time. Alien as a horror film is encased in the atmosphere of a cold space, underlined with a tension and scares that few films can emulate, whether it is Dallas's lonely walk through the air vents or Kane's rather unhealthy meal. As a horror film is arguably the greatest of all time, yet it is also simply one of the greatest films of all time as well. 

5/5