Demolition Man Achievement
Online: get 20 demolish kills
Demolish kills are when a building collapses on someone and kills them. To know it counted as a demolish kill, watch for when it will say "Demolish 2.0" as the weapon, just like in the campaign for demolishing houses. There must be enemies inside of the house/building. This may be the most time consuming achievement in the multiplayer since it is so rare to find a building that can collapse and actually getting it to collapse on an enemy. An easier way is to call in mortar strikes with the Recon Kit on objectives in the "Rush" game mode. There are bound to be enemies inside, and it will weaken the building and possibly cause it to collapse. Just look for the areas of buildings/wall that have not been blown out yet, and call in a mortar strike on that position.