Not sure if I can explain it well enough, but I'll give it a try. To pass the NCLEX, you aren't merely answering questions as 'right' and 'wrong'. Questions fall into different levels; at some point in your exam you will have a greater number at or above the passing standard than not (and you pass) or your test questions tend to fall more often below the passing standard (and you fail).
You might be getting a bunch of questions wrong, questions that are rated as 'above' the passing standard. But you didn't get them correct....so it kept dropping you further and further below, to give you questions you DID get correct, but were still too far below the standard to pass.
It's a computerized scoring, that grades based on what LEVEL of question you were getting right (and wrong). Simply telling you that you got Question #100 wrong won't tell you much, if that question was so far above the standard it didn't matter if you got it wrong. Same if you got Question #200 right: ok, you got it right....but it was so far below passing standard, IT didn't matter either. It was too easy, so not a passing-level question.
Something to keep in mind, too, is that on EVERY exam, there are a certain number of questions that are known as 'pilot' questions: these are questions that DO NOT COUNT in your score. You might get them all right, or all wrong. Doesn't matter. They are there to be gauged as to whether they might be appropriate to use in future tests, as 'real' questions. So, again, telling you what is right or wrong in all your answering won't do much to help you study if you failed, and it's irrelevant if you passed.
Does this help explain the Wizard?