This video by Andrei Petrov gives an indication of the level of destruction in Slovyansk after weeks of constant shelling by the Ukrainian forces surrounding it.
An article published in the Guardian on June 12 gives a vivid description of it:
“Tens of thousands of people are fleeing combat, most of them from the rebel capital of Slavyansk, where almost daily shelling has claimed numerous civilian casualties since late May. Most residents in the besieged city have been without water, electricity and gas for the past week. Food supplies are limited, and grocery stores smell of rotting food from the lack of refrigeration. ” (Appalling conditions force exodus from Slavyansk as daily shelling disrupts food supply)
Here’s another video by Andrei Petrov of the destruction in a block of flats: