I am trying to make a scene like in this video here:
Well, offhand I would start by taking a flat plane and carving it up into randomly connected line-segments. (Undoubtedly there’s a “shatter” script for that.) Then, this is extruded downward to form three-dimensional shapes. Next, each of the polygons cum shapes is separated to form a distinct object.
When they are perfectly aligned, as in their starting position, they form a cohesive whole. There literally is no “gap” between them. But now you can animate them, e.g. with Physics, so that they split apart, crumble into the nether-regions, or what have you.
The basic technique that is being used here is simulation: the animation probably isn’t generated by keyframing (although a good bit of refinement might be done that way). Instead, this is (in the world of Blender) the domain of particle-sims, the Bullet physics engine, and a whole lot of Python code. However, since this is an open-source world, people share that kind of stuff quite freely.
There are many, many composite layers that go into an effects-shot like that: sometimes several hundred. For example, there will be lots of particle-driven action, smoke, flying objects, body parts, “dogs and cats living together … real Wrath of God stuff …” 
And this is all built-up one bit at a time.