That was an incredible performance. I didn't know it was off the cuff. Pretty amazing. I watched the movie with my dad who was in the Marines in the 1960s, and he thought the basic training part of the movie was pretty realistic.
I've got a friend in the Marines, and he's told me that it's pretty different nowadays with respect to the Drill Sargeants, but the camraderie among the enlisted is pretty much the same.