I played this about yesterday and I even knew how to go out of bounds by crawling under one of the trees that it looks like that you could crawl under like if it was a solid that can not be moved. But basically I had got onto the area where the cars are moving and when I got hit by one, I was fine like if it was nothing. But one thing that surprised me was that the whole area where you have the trucks and cars lying around and there was supposed to be water but somehow there aren't and there is the huge boat where you have to go inside, was under the surface that you start to get to the ocean and get the skull that is in the truck. Yeah, and I got in this (huge boat/titanic) while in the normal world and the place wasn't completely filled with water and I could wander around and not die of being out of air.
So you know the whole game, right? Well, when you go back to the normal world from the titanic where you put the skull onto the human corpse there is still the skull in the truck. And when you pick it up, the game seems to crash.