How hard IS the AP World History test?

I've been studying here and there over the course of this school year for this "prestigious test", however, it seems like a bit of a game. For example, my friend took it two years ago and did very well on the multiple choice and only wrote ONE, not two, not three, ONE of the essays, and he still finished with a passing grade, a three. Also, this calculator along with others seems like it isn't a terribly difficult test. And, if you write some false facts on the comparative and the CCOT will the editors REALLY know? I mean, if it's written well but contains a couple false facts WILL THEY CARE? OR EVEN KNOW? I'm testing May 14th, and studying pretty well, so I'll probably be ready, but I want to just know the answers to the questions:

1) How hard is it?

2) Will a bit of false info slip by and if not will I be marked down.

3) Does that calculator seem legit, and the end result make sense.

Thank you!