What is this Korean thriller/horror movie?

The plot is, contestants on a "game show"are stranded somewhere in Australia. At first they believe it's a harmless game show, but they realize it's a game of life or death when the find the first eliminated man in the woods in a swamp with an arrow stick inside him. Eventually it's revealed that the man who set up the game show wants to punish them, because a few years ago, in a convenience store all of them witnessed his wife get brutally murdered (on the day of their anniversary, I think) and didn't do a thing to help her. One man even took out his video camera and video taped every second of her assault, till she was dragged out on the street and stabbed.

I remember one of the characters name was Mr. Han , and another was Ms. Jo

One character was fat, and died of dehydration in a dessert,

the really competative one drowened,

the bubbly, pretty girl was shot with a crossbow,

the nerdy girl was stabbed and murdered by her insaine "boyfriend" who eventually realized that in order to escape, he needed to be the last one alive.