-Play Wesker's Mansion Mission (Rebirth) and play the first scenario repeatedly. Once you find all three files, all you need to worry about is critical hits and time. It‘s a short mission so playing it repeatedly doesn‘t get tedious. Once you get the three files, getting an "S" rank is easy. Get all your critical hits after going up the steps. Once the zombies begin moving, aim your crosshair until the red circle blinks, then fire for an instant critical. Also, be sure to always throw grenades into groups of enemies.