This is one of the thoroughly enjoyable monster movies that appeared amid all the camp and trash the genre churned out in the 1950s. While it is no masterpiece, there is nothing worthy of serious criticism. The movie is well-paced with plenty of action--the viewer is not required to wait 45 minutes before anything at all happens. It is very well filmed, in a widescreen format (the only way it should be seen). And the acting by an exceptionally attractive cast is above average for this kind of film.
As for the dinosaurs, they may not be up to the standards of "Jurassic Park" or "Walking With Dinosaurs", but, again, considering what the budget must have been, they are rather good (except for a slow-moving Tyrannosaurus).
What really makes this movie worthwhile is its atmosphere. It draws the viewer into the reasonably convincing world of a tropical jungle in the middle of a polar icecap.
A very likeable and exciting movie. See it in widescreen if you can.