I have been denied a run for "duplicate" and I do not understand why if it meets all the rules of the run

The link is this and is in the section Dr. Kahl's Robot: Highest Grade - Co-op, Simple, Legacy (Sorry for my english)

I’ve seen that there is an exact pace of changing weapons to do more harm, what is it? Because I do less harm than a friend of mine and I spam much faster

Add a category for each world separately