Branching in Storyline / Variables

First, you don't have to duplicate scenes to show different characters. That's hard to develop and hard to maintain, since all changes/corrections have to be done in multiple locations. 

Instead, you can use a variable to track which character was chosen. Give the character-object a custom state for each character. And trigger which state to show based on the value of the variable. Details are in this article: 

• https://community.articulate.com/articles/allow-learners-to-choose-an-avatar-using-one-variable-with-storyline-360 

As for variables to track which levels are completed: For each level, create a T/F variable with a default value of False. At the end of a level, add a trigger that adjusts the associated variable to True. On the status slide, have triggers that show a level as completed (e.g., change to a custom "Completed" state) when the timeline starts with the condition that the associated variable = True. 

This post is about custom menu slides. But those use similar programming, so you might find the demo file useful:  

• https://community.articulate.com/discussions/articulate-storyline/create-a-custom-menu-slide 

Here is the User Guide info about conditions and variables: 

• https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-work-with-triggers#conditions
• https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-work-with-variables