Many years later, Alien remains a masterpiece of tension thanks to the power of its physical performances.

Giger was rightly handed an Oscar for his part in the seductively hideous xenomorph in its various stages.

The films story and nightmare imagery is still picked over for its Freudian and feminist subtexts.

The aliens barely glimpsed, but we feel its presence because the crew seem so believably scared.

This minor epiphany occurred while watching television in a rather cramped French hotel room.

Flicking through the channels, I stumbled on a late-night showing ofAlien, understandably dubbed into French.

These arent all-American astronauts, but rather a motley collection of navigators, engineers, and scientists.

They bicker and squabble over bonuses and pay.

Some of them resent each other.

Others appear to have been in a relationship in the recent past.

Ian Holm is faultless as the duplicitous science officer Ash.

And of course Sigourney Weaver is brilliant as warrant officer Ripley.

Lets take Ian Holms Ash first of all.

Holm brings a keen intelligence to the part, but also a fidgety, passive-aggressive edge.

He bears an obvious resentment towards Ripley almost from the beginning.

Note too how calculating he is.

Before the infant alien even stirs in Kanes stomach, Ash knows exactly whats going to happen.

He just doesnt know when or how.

Part of this is thanks to good, old-fashioned trickery on the part of the filmmakers.

Again, shes sublime casting.

Cartwright understands that, when people are genuinely scared for their lives, they dont look pretty.

By contrast, Tom Skerrits Captain Dallas is the crews sturdy, dependable center.

In an earlier period the 50s or 60s, say Dallas probably would have been the films star.

ButAliendoes something audiences werent used to seeing in the late 70s.

While gamely hunting the alien through the ships ventilation shafts, Dallas winds up as its third victim.

Lambert teeters on what comes off as the edge of nervous collapse.

The imposing Parker (Kotto) reacts to the situation with a kind of impotent rage.

(Kotto would often say to Scott, Im not gonna die today!

to the point where Scott would actively avoid the actor on set.

I think this attitude feeds into his character.

Hes the only one who goes down fighting, or at least tries to.)

Its fascinating to see how much commitment the actors put into these scenes.

Some actors might have looked at the script, saw anIt!

The Terror From Beyond Space-jot down B-movie, and simply coasted through the shoot.

Instead, they attack their roles with obvious intensity.

You had to walk the whole way round its web link of corridors and atriums to escape.

Maybe it was this sense of claustrophobia that helped the actors absorb themselves so completely.

It helped me find the character.

Sigourney Weavers brilliance really comes to the fore in the final act.

And again, its an almost pure physical performance.

Indeed, nobodys seen the alien and lived.

A stereotypical scream queen character from a slasher movie wouldnt have survived inAlien.

Although not without charm, movies likeTitan FindandGalaxy of Terrorfailed to captureAliens grimy sense of realism.

Indeed, Scott himself couldnt quite recaptureAliens magic in his own prequel, 2012sPrometheus.

As Ridley Scott has admitted himself in the past,Alienis still a pure B-movie at its heart.