Published on May 6, 2008 Your best shot at this achievement is to never replay a mission so if you die go back and load your save point and time resets to the time you made the save point.
I did all the missions except rounding up the cars and assassin missions and still had 15 min. left to work with.
Published on April 30, 2008 You must beat the storyline in under 30 hours, after you beat the game you will be able to go back and beat side missions. To check your playing time