In horror movie terms, Primal is nothing new or original. It follows a very predictable path of the whole "young people camping in the woods with a monster" story. The characters are fairly predictable, as is the ultimate ending.
What makes Primal stand out, though, is, aside from the Australian Outback setting, the monster itself. Sure, the general idea is pretty standard, but the actual character of the monster is one that, at least for me, is new and exciting. Definitely pulling from the name of the film, the monster is very animalistic in its movements and behavior, but what was most exciting is the bridge between man and beast that it creates. This is perhaps the most terrifying part of the entire movie; the hinting of ourselves from, relatively speaking, not that long ago.
Sadly, all of the tension, thrill, and the interest of our primal selves completely falls apart in the last twenty minutes or so, as it seems that the filmmakers blew their budget, in terms of both money and creativity, as we get a terrible and confusing climax full of horrible (especially by 2010 standards) CGI which hurls us through the wormhole (you'll see) to the expected, but not entirely bad, conclusion.
Oh, and one of the best, and most Aussie, ending lines to any movie.