This is about as straightforward as a contest gets: blow shit up in a video game set on an island in order to win yourself a real-life island.
You enter by getting a "Day One Edition" version of Just Cause 3, which is available via pre-order and in stores right around the time the game launches. To participate, you simply earn Chaos Points in the game by destroying anything you can find. The person with the most points by the end of the competition on Feb. 29 wins. Simple.
The fine print makes it clear this contest really does win you an actual island. "One (1) Grand Prize Winner will win ownership rights to an Island, valued at up to $50,000 USD or $50,000 USD in cash. Location of Island to be determined by Sponsor."