Do not wait for the popping sound to end, or you will burn the popcorn.
There will be some unpopped corn kernels in the bag. That is A-OK!
Every microwave is different. Some take as little as 1 minute, while others might take almost 3. Once you make the popcorn, you will have a clear idea about the actual cook time for your microwave.
As far as flavoring goes…..sky is the limit. Add salt, cheese, brown sugar, nutritional yeast, honey….what ever you heart desires.
I have tried making the popcorn without adding any oil in the beginning and though the recipe works, the popcorn wasn’t yummy.