Draw With Me/WMG

The glass wall is really the Berlin Wall, and the boy and girl live in West and East Germany respectively.

 * In the bonus video, there's some writing about "The Elder", so her side seems to be stricter, and she was generally colored in red-based colors. COMMUNISM I SAY!
 * OP here. I forgot to add this one point. It looks like the girl only has that tiny dress, and presumably leggings, while the boy has that tank top and those shorts. Suggesting a higher abundance of clothing resources in the boy's West Germany.
 * Not the OP here. Along with this theory, when the boy writes to the girl if she can write, it had nothing to do with literacy and ability. It was about whether or not she was allowed to.

The Glass is

 * The girl is dead and the boy somehow can communicate with her spirit, but he wants to hold her, and attempts to, aka  . It fails devastatingly and the boy , unable to hold her like he wanted to. See the Irony here? Read  and you might see the similarity here.

The two sides have nothing against each other and would actually get along quite well if allowed to meet.
It's The Wall that wants them seperated. Why? Because it's a Jerkass.
 * But it may serve a purpose. Maybe it wants to protect one side from something about the other side, like an infection the others' immune systems can't block. To be more specific...
 * But then why does it block sound? And why does it let objects (that could be contaminated) through?

The Wall was put up by CEDA to trap infected.
The boy's just turning slowly. Which explains why

The wall is Made of Indestructium

 * The Wall's damage caused a paradox that the universe had to quickly reverse, lest the hole in the wall become a black hole.

Someone cooks the girl's arm.
Nausea Fuel, anyone?

The world the boy and girl are in is where all Bags of Holding deposit their contents in

 * Somehow people got trapped in this World of Holding, and formed a society in them. The glass wall is a magical barrier to prevent the contents of one bag moving to another. Since charcoal and arms can go across, clearly it's not as strong as it seems.

The two are in Faerie.

 * The two have been captured by the same Keeper and the wall serves as their Durance. So while the two are trying to communicate with each other and suffering, some True Fae is giggling its sick ass off as it watches them.