Itamar Tzadok

If you backup/restore with user info you should get the entries and files.

The Database module can allow you to create forms. The Dataform module can allow you to create more complex forms.

What exactly do you mean by "academic application process"?

Which version?

Does it happen with all groups/students or only certain groups/students?

Getting back to your proposal

Answer 1, correct, 50%
Answer 2, incorrect, 0%
Answer 3, correct, 50%
Answer 4, incorrect, 0%
Answer 5, incorrect, 0%

When participant marks two answers, he should get either the 100%, 
50%, or 0% of the question score, depending on the selection. When 
participant marks more than two answers, he should get 0% even in the 
case he marked some of the correct answers.

It has been a while since I worked directly on question types but I think that this could work if you marked the incorrect options -100%.

Answer 1, correct, 50%
Answer 2, incorrect, -100%
Answer 3, correct, 50%
Answer 4, incorrect, -100%
Answer 5, incorrect, -100%

Insofar as negative marks are translated to 0, any combination of two or more answers where at least one is incorrect would yield 0. Only the two correct answers would yield 100%. Only one correct answer would yield 50%. Unsuccessful guessing would yield 0 (successful guessing is as good as knowledge for all the teacher knows without cross-questioning). 

I don't remember if that's a standard behavior or the behavior of a variant of the standard multichoice I developed and used. I even put in the code of that variant a note to myself that not choosing incorrect answers also reflects knowledge (or successful guessing) and in some strict sense should be rewarded just as choosing a correct answer, thus making the marking pedagogy even more complex than it already is. Time permitting I will go back to that variant question type and release it as a plugin, although, being a multipurpose question type, some may find it's flexible configuration UI too flexible.

... which after all seems to suggest that the observation that we don't have an answer yet is not provocative. The rising popularity in recent years of cognitive science research programs and institutions also suggests that the observation is not provocative. It's premise is that while many disciplines, such as developmental psychology, may have important contributions to understanding how this thing called us works, each discipline in itself may not be sufficient for a systematic understanding, let alone when the discipline is far from unified.