Arriving on the island, thy find what appears to be the remnants of the rave, a few tents and a stage, completely deserted with the only evidence of a previous human presence being some garbage and blood.
Now, here is where many horror films, including this one, go terribly wrong. You and your friends arrive on the scene to find everything abandoned and blood everywhere. In the real world, you would get back on the boat, go back to the mainland and party at a local club, and maybe call the cops. In movie world, you and your friends become the Mystery Inc. gang short one Scoobey Doo, and investigate.
Not freaking likely.
The acting is simply awful, and the plot meanders from flash-backs as the tweens piece together what happened, nude-scenes (not worth it), zombie encounters, and the introduction/demise of a number of auxiliary characters that should have been the focus of the film who actually have some clue as to what might be happening (who, instead of getting the civilians off the island continue on with whatever their mission may be). Worse, the major fire-fight between the survivors and the hoards of on-coming deadies is inter-spliced with cut-scenes from the video-game. If you were actually into the film, the cut-scenes effectively disengage you.
As if you needed another reminder that you are watching one of the lamest films ever made.