***SPOILERS****
Don't read if you're sensitive.
I remember watching this once, and only once. I usually watch movies time and time again if they're good, and especially if they're based on factual events.
But my question was, 'based on factual events' according to whom?...
The remaining survivor spent the second part of the movie tied up and out of sight of his fellow travelling companions which basically means that the second part of the movie, the most thrilling part, is all made up. They hadn't seen their friends being killed, how they were killed, where they were killed, etc. So it meant that from what the survivor remembered was that they were all having a great time, laughing and joking in front of the camera, found a friendly local, woke up after being drugged all tied up. That's it. And that would be all the movie would be based on.
After doing a little digging, I found this: Wolf Creek is not directly based on a true story, although a title at the start says, 'based on actual events'. It was suggested partly by the gruesome details of the backpacker murders committed by Ivan Milat in the 90s, but these murders were committed in a state forest near Sydney.
Is it a good thrill to watch? Sure. But I remember even back then thinking 'that didn't make sense', so it kinda ruined it for me and destroyed the whole illusion.
Still worth watching as long as you don't get hung up on hoping the main part of the movie was a reality once.