10 Horror Movies You Must Never Pause

Ridley Scott's Alien is for the most part a masterclass in subtlety, of building tension through atmosphere and what you don't see rather than relying on splashy effects.

Scott smartly keeps the Xenomorph concealed for most of the film, ensuring the artifice of its creation never draws too much attention to itself.

There are a couple of iffy special effects shots, though, most notably during the sequence where malevolent android Ash (Ian Holm) is burned to a crisp for trying to murder Ripley (Sigourney Weaver).

Though Ash's talking severed head was achieved through the elegantly simple practicality of having Holm poke his head through a hole in the table, for any shots where Ash is moved around, an unconvincing papier-mâché-looking head replaced the actor.

And so, when Ripley knocks Ash's head over, the cut between Holm and the prop is comically jarring, not to mention that when Parker (Yaphet Kotto) torches Ash with a flamethrower, it's momentarily clear the prop has no articulation of Ash's facial features whatsoever.

For an otherwise magnificently crafted film, this is oddly sloppy.