What does "Flexibility" mean in Hotline Miami scores?

I started playing this game yesterday, and I've consistently gotten 0 points for flexibility. For the sake of it, I altered my play-style, using every weapon and method to hand. No joy.

How do flexibility points get awarded? Perhaps this feature is bugged?

I've never gotten anything other than 0. My guess is that they didn't finish adding the code that measured it, and it would have something to do with how much you used and reacted to the randomized spawns (weapons on floor, held by enemies). That sounds difficult to assess fairly, and usually the randomization doesn't affect your run that much, which, to me, explains why it's not working. I bet they'll just remove it and maybe add a different category later in a patch.

Again, total guesses of mine.