Triggers

There seem to be some extra triggers here so that may be throwing some wrenches in your project. Some of your layers for instance are set to play audio if the HTN box variable is true, not their own variable. I also don't think I understand why your layers are pausing toward the end, and then only after they've been clicked again to return to the base slide layer does the boolean variable they're assigned flip to true.

I think the main culprit is your trigger that Sets the state of the NEXT_BUTT2-"U" button to disabled. I can't find a place in the project where the variable it checks, ClickEachRevisited is changed to true, which means visiting the first slide will always trigger the button to disabled since the variable is always false. I added a trigger to the second slide's back button that changes the variable to true, and now the button is in the normal state when I revisit it.

That also eliminates the need for that Disabled trigger to check each of the BoxN variables. If the learner made it to the second slide, that's the proof they already viewed everything, right? So the one "is the learner revisiting this slide" variable should be enough.

Additionally, your Transparent layer that blocks the user from clicking the buttons is hiding the first time the slide viewed, after the base slide timeline ends, but when the learner revisits the first slide, the Resume Saved State of the base slide keeps the playhead at the end of the timeline (because that's where the learner left it, right?)

A consequence of that is that Storyline's "when the timeline ends on this slide" trigger doesn't re-fire, which means revisiting the slide doesn't re-hide your Transparent layer. It stays up the whole time, which is why I'm prevented from reclicking the buttons. I'm not sure if it's a deliberate design choice to both hide the cards upon revisiting as well as to prevent the learner from clicking them (then why am I revisiting the slide?) but I thought you should know.