How long does it take to complete Metal Gear Solid 1

The fastest ever completion of Metal Gear Solid with one life and without saving is 1hr 55min 31secs. but depending on whether or not you have played the game before will vary your finishing time. if you like to take your time, grabbing all the guns and items and save Meryl while watching all the cut-scenes, you'll be enjoying about a 4 to 6 hour ride. on the other hand if your just blasting through then maybe more like 2-3 hours. also the games difficulty level will effect your final time due to the harder levels having longer boss fight, increased enemy presence and a lot fewer items to find.
hope this helped ;)