The Cop started as a strong leader who never gives up and used his authority to set people straight and keep them sane but in the end breaks down into a psychotic and delusional asshole who uses his authority to play god and attempt to rape The Student. Watch it and watch for the part where he talks about reading people's minds. He'll mention this again later, but using a very different tone that gives the first one the shivers.

The Employee was initially a bitchy bad guy who kept to himself and was actually responsible for putting everyone in the cube and called the entire affair pointless. By the end, he was rather helpful and hopeful and became the de facto leader of the group until the end.

The Retarded guy was literally The Load. He was useless, unkempt, and undesirable. We both know what happened to him in the end.

and so on. this happens to every character.

And yes, even the first 2 minor characters have this distinction. Renne the "Master Escapist" showed absolute proficiency when he first appeared, only to be outsmarted and broken in his last appearance. The first character of the movie was billed (if you seen the poster) and portrayed in the opening sequence as the supposed Main Character...only to not be.

Symmetry is everywhere in this movie.