Track Multiple Completion Criteria

Storyline allows for tracking a course via a Pretest or a Final Assessment. 

• If the user passes the quiz that's marked as a Pretest, that's submitted to the LMS as successful completion.
• If the user doesn't pass the Pretest, that score isn't submitted. Instead, they'll have to pass the Final Assessment. 

It sounds like you don't want to require users to answer questions and pass a Final Assessment. However, you could include a disguised question slide and Results slide to use for tracking. 

• The question slide could be anything that asks them to click a button—with that button being the "correct" answer. This could be a standard or Freeform question slide.
  • Turn off feedback, so there's no Correct or Incorrect layer. 
  • Use the Slide Properties to turn off the Submit button and show the Prev and Next buttons.
  • Put the Submit [interaction] trigger on the Next button. 
• Another option for the question slide: 
  • Put an object with a Normal state and a Selected state off the slide.
  • Convert the slide to a Freeform pick-one question slide.
  • Indicate that the off-slide object is "correct." 
  • Add a trigger that changes the object to Selected when the timeline starts.
  • As with the other option, put the Submit [interaction] trigger on the Next button.
• Redesign the Results slide however you want. You don't need it to show a Success or Failure layer. You just need its Submit Results trigger. And indicate that this is the Final Assessment.