Storyline 360 - quiz questions - multiple attempts - points awarded

A multiple-choice question allows you to give partial credit for okay-but-not-the-best answers.

You could use that functionality to assign points based on the number of attempts, which would be tracked with a number variable. 

The trick: The actual multiple-choice responses are hidden from the user. Instead, use triggers to "select" the appropriate response/points based on conditions that check (1) whether the answer is correct, and (2) how many attempts have been made. 

You might find this post and its demo file helpful. It's also about disguising a standard multiple-choice question to take advantage of the score-by-answer function: 

• TIP: Give Partial Credit on Multiple Response Questions | Articulate - Community 

Yes, it'll take some doing.  However, after you get one question working, you could duplicate that for the others. I think that would be easier than handling multiple versions of each question.

And it’s worth the effort to learn about variables and trigger conditions, because they provide the real power in Storyline. Here’s more information:

• This post provides an overview of variables. It also links to numerous resources.  The Value of Variables | Articulate - Community 
• The User Guide section about triggers includes info about conditions.  Storyline 360: Working with Triggers | Articulate - Community