They have been developed to pick a single object and vaporize 25 mile radius.

All living organisms from man to ameba instantly gone

Those who were lucky enough to be within ground zero feel nothing

Those outside ground zero feel the pain from the blast

They feel the pain of their skin being ripped right off exposing the nerves,

the tissue, the muscles and finally the bones.

Others might not be in close enough proximity to the bomb to be killed

But they feel the after effects not the ash settling in suffocating everyone it touches