Gamification Design Question

You could use a dial for this with a number range 0-20. Starting value 0.

A correct answer: trigger adds 1 to that variable. That will move the dial. Put a hotspot over the dial, so the user can't turn it.

Since the titled is earned based on the value of the dial variable, you show the title on the title when the variable = X (or is within a specific range)

And when they get to the end on another slide, you can display something based on the specific value.

Here's a quick tutorial: https://a.cl.ly/eDueKrX5

Alert: Covering a dial or slider prevents someone from dragging it with a mouse. However, it doesn't prevent them from accessing it with a keyboard. I just found this out today from a comment Steve Gannon made on another post: 

As Steve said, you'll need to remove the dial/slider from the Focus order. 

Since you're using 20 questions, I suggest putting the dial on the Master Question Layout. Then, as Tom said, have a trigger on each question that adds 1 to the dial's variable when the user clicks the Submit button if the the correct answer = Selected. Be sure that trigger comes before the one that submits the question. 

Here's info about removing a Master item from the focus order: Focus Order | Review 360 (articulate.com)