Need Help with a Storyline Drag-and-Drop Activity

There are definitely some simple solutions, though due to the number of objects and slides, it wouldn't be fast.

If it were me, I'd create a true/false variable for each draggable topping called something memorable like mushroomCorrectA, mushroomCorrectC, etc. They can be false by default, and then each draggable has a trigger that sets the value of its relevant variable to true when the state of the object is Drop Correct.

Drop Correct is a default state each draggable object can have, often used to change the appearance of the draggable once its dropped on a correct target. Your toppings don't currently show that state, but it will be listed in the dropdown of the object's Add State dialog. When a topping is dropped on a correct target, the object will then automatically change to that state, though the learner won't know if the states appear identically.

That state change can still be used to trigger that variable flip. Then, a second trigger can change the state of the object from Drop Correct to Disabled when that variable changes, locking the learner from interacting with it any longer.

So:

1. Learner releases an object over the correct target.
2. Storyline changes the state of the object to Drop Correct.
3. That triggers a variable to flip to true.
4. The variable changing to true triggers the state of the object to become Disabled.

Those variables will also help shuttle the learner to the next slide. Again this'll be a lot of triggers, but one could create a trigger for each of those variables that goes to the next slide when the variable changes to true if ALL of the variables are true.

That example only shows two, but you'd need to add an "and" for every is-it-correct variable on that slide.

I like your implementation, and can see it's really coming together. Some of my impressions from a usability perspective are that the "ORDER#" text is hard to read. The R looks like an A, and the number is so close to the word that it risks being interpreted as a letter (5 looks like S in that font.) Since children in your audience's age won't be able to read or understand the word "order," I wonder if just the number wouldn't be simpler? Your Next Order button will likely benefit from a similar redesign, perhaps just being a round button with an arrow pointing to the right? Symbols will be much easier for them to understand.

To provide positive reinforcement, I think I would also recommend an extra "Yay, you did it!" layer rather than just jumping to the next slide when all of the toppings are added correctly. The jump would seem sudden to most people, so a layer appearing with some musical fanfare, some text congratulating the learner, and so forth would go a long way. Then a trigger on that layer could send learners to the next slide once the layer's timeline has ended, but that extra five seconds of validation supports the design of the learner's experience.