Lowbacca’s review published on Letterboxd:
Right off the bat, Gary Cooper was really a miscast here, the character is meant to be young, and indeed there's dialogue that really rather requires that, and Cooper at nearly 50 simply doesn't convey the right feel. That was apparently at Ayn Rand's request so we can count that as but one of the many flaws in this film that fall to her.
The plot, when looked at in isolation, could certainly work. Parts of it at least. The problem is that plots are about people, and The Fountainhead utterly fails at having people in it. The characterizations come off as absurd, in large part because the way that characters talk are so unbelievably hamfisted that I would be very hard-pressed to think of anything I've seen that tried to force a philosophy in to every line as this does. It really just doesn't work at all, and makes this excruciating. This poor writing apparently comes from Rand wanting stuff to be exact to how she had written it, and it simply doesn't work in a movie.
I will grant it that there's some good production value to this, and some good shots. It would just be able to do a lot more with decently written source material.
After watching this, it seems a very good thing that this experience convinced Ayn Rand to not allow films of any more of her books to be made during her life.