59:56. I beat the game. 50.48 I beat the game again on hard mode. Also, on hard mode I managed to take out over 30 guards by turtling in and out of cover. After the main mission, I thought I was about to get another one, what with the content of the cutscene, but nope. I did think the gameplay was fantastic, aside from the fact that it was to easy to go through guns blazing if you have any sort of skill at shooters.
I'm eager to explore more of the base now, but I really hope these shooter aspects disappear by the Phantom Pain.