I always loved, absolutely loved novelizations. They gave you so much more information, and so much more insight that you cant have in the movie, or there just isnt a place for it. The ALIEN novelization has couple interesting things going for it, which I listed in my blog which I dont want to shamelessly plug so Ill just paste it here:
1. Nostromo's oil is being processed during the return trip
(...) Nostromo was towing a considerable quantity of crude oil through the void between the stars, encased in its own automatic, steadily functioning refinery. That oil would be finished petrochemicals by the time the Nostromo arrived in orbit around Earth. (pg 21)
2. The planetoid is still Orange
As in the early concept paintings and illustrations, the planetoid isn't dark as a night, but it's a mix of bright orange and brown colors. Some examples
They moved without talking through the dust-laden, orange limbo (pg 63)
The increasing brightness didn't help. Instead of raising their spirits, the rising sun chilled them by turning the air from orange to blood (pg 65)
3. The gravity is slightly lighter
If someone was ever wondering if it wasn't too hard for Lambert to help Dallas carry Kane all the way back to Nostromo on stretchers, the gravity on the planetoid was lighter than that of Earth
The slightly lower gravity eliminated the burden of suits and tanks (pg 62)
4. Facehugger has an eye
Like in the early concept illustrations, in the novelization the facehugger still has one dark eye on its "back". Example:
On its back he could just make out a dim, convex shape that looked like a glazed over eye. (...) The eye moved and look at him (pg 95)
5. Ripley also replaced the last officer
Just like Ash, Ripley replaced the last officer
So what? (Dallas) snapped at (Ripley). They also replaced my old warrant officer with you (pg 151)
6. Kane was out for a couple of days
"God am I hungry. How long was I out?" Dallas continued to stare at the apparently unharmed man in disbelief. "Couple of days" (pg 166)
7. The chestburster is still of the original design
The chestburster is still the original Chestburtser design done by H. R. Giger based on the Francis Bacon painting
It reminded Dallas of a butchered turkey with teeth protruding from the stump of a neck (pg 172)
8. Apparently Ash was lying about the crew's chances against alien
While Ash revealed his admiration for the creature due to its adapting capabilities, it seems that he over exaggerated alien's characteristics in order to spook the crew into fixing Ash. It is made much more apparent in the novelization with additional dialogue of Ash like this:
"I don't think that you can kill it. But I may be able to. (...) However, I am not exactly at my best at the moment. If you would simply replace..." "Nice try Ash" Ripley interrupted him (pg 253)
He then tries to explain that the alien may infect the Earth's population if he arrives on the ship and tries to convince them that if they won't reconnect Ash to help them, they will have entire Earth on their conscience
And just by the way, this is the alien's first description which I think is terrific
"Above the helpless figure of the engineer was a faint outline, something man-shaped but definitely not a man. Something huge and malevolent"First US printing