About 35 hours on the Origins version. Didn't play any other versions of the original besides that. Pretty difficult without a guide and no understanding of what a real RPG was like (like running 5 feet in the wrong direction at Lvl. 6 and fighting a Lvl 50 dinosaur or something....oh and you forgot to save lol).

EDIT: Oh but I see you meant the total time even when the game was turned off? Probably like 15 days my only time through.