All in all, it isn't bad at all. There are differences throughout on A-Deck; the seating 'alcove' in the galley is mirrored compared to the movie (screens on the left as opposed to the right); the Bridge has some differences such as missing evac helmets on the rear left and right seats, the viewports look different....B and C decks (from what we see in the movie) do look quite a bit different (ladderways not lining up too well, the upper catwalk around the landing leg, which by the way, I just found Brett's body there, that was neat). I think I like C-Deck the best, captures the overall aesthetic of the film very well. Unless they have time and budget to make it completely accurate (I don't make games so have no clue how it all works), I think what we got is great.
Over on
Propsummit.com, we are gearing up to work on new internal Nostromo blueprints similar in vein to the ones that were with the Alien: Vault book. I've started the brainstorming process, figuring out layouts, scale and what is on each level and others have provided input on that also. :-)