What differentiates the design of an "explosive" play from a normal one? It sounds about as obvious as saying "we can win if we score more points than our opponent
"Explosive plays" are defined, for whatever reason, as a running play that gains more than 12 yards and a passing play that gains more than 16. I like to keep it simple and leave it as any play that gains more than 20. It gets further qualified by down and distance considerations. A TD pass of 15 yards would be considered to be explosive. A run of 13 on third and 16 might be considered to be explosive, but kind of defeats the purpose of the designation.
Hard to identify a running play that is designed to go for more than 12 (or 20). Pass is easier.
Frankly, it's a semi-bullshit metric. But keep in mind we're dealing with a group in which the guy with the National Geographic subscription is considered to be an intellectual.