I watched all (four?) of these recently. It was interesting to have some of the more common images given some proper context, and there were quite a few I'd never seen before, particularly on the engineer side. As much as I quite like the direction they took with the engineers in the finished film, some of the designs he did after the fact, which retro-engineered the original jockey design (excuse the pun), are right on the money.
I think he other creature designs are maybe 75% miss to 25% hit in terms of what would work on screen, but at the end of the day his role was to spit-ball ideas and open up the possibilities to that Ridley et al could whittle them back down. Probably the biggest takeaway for me is still the damage done by moving away from the xenomorph in Prometheus in favour of Lindelof's "mystery box-esque" nonsense. There is a clear evolution in the original designs for the deacon, neomorph, and ultramorph that's completely lost in the finished film.