Tetris/WMG

The whole thing is an abstract metaphor for Death Note
The S-shaped piece is a shimigami. The I-shaped piece is Kira, because it "kills" several lines. The L-shaped piece is the L. The T-shaped piece is Tokyo police.

One of the pieces displays Obfuscating Stupidity
The L-block is running a Xanatos Roulette. It all fits together in the end.

The real reason the Soviet Union fell...
Is because between Tetris, Zerg Rushing Hitler, and putting a man in orbit, the Soviet leaders realized that their nation had fulfilled its purpose.

Tetris is a mind-control device created by the Soviet government.
It didn't name The Tetris Effect for nothing. Tetris has no real right to be as addictive as it. Instead of watching the news, educating yourself, or meeting girls, you were playing Tetris, which has no Real Life application. Tetris was invented to weaken the united states, one citizen at a time, making it easier to take over in 20 or 30 years.
 * The Tetris Effect is not what you think it is. You weren't playing Tetris instead of those; you were playing in your mind while doing those. This is pivotal to the mind-control device.
 * Unfortunately Tetris weakened the Soviet Union faster than it weakened America. The Soviet Union fell first because of this and the rest of the world will collapse 2012.
 * The Ancient Mayans knew about Tetris.
 * The Mayans knew about Tetris because they had a primitive version of it that ultimately lead to the collapse of their empire. They simply predicted its re-emergence.

All of the blocks are sentient and have lives outside of making lines
This is just their day job. They're all a group of friends and coworkers whose job it is to make walls out of lines. Sometimes they have off-days and they miss a couple of bricks, though.

Tetris is
The very lowest level of hell. Think about it. It's for the very worst people, the serial killer rapist arsonist litterers of the land. People are turned into Tetris blocks and forced to eternally make lines. If the screen fills up, they are taken away to be tortured.

Tetris is a metaphor

 * ... For capitalism:
 * Numerous disparate blocks of all shapes and sizes trying to work together, wouldn't it be better if they were all built the same way?
 * No matter what you do, the construction will keep collapsing from underneath you, symbolizing both the futility of attempting social progress in a capitalist plutocracy and the inevitable revolution of the underclasses, tearing the old society down from the bottom up.
 * ... For communism:
 * Numerous disparate blocks of all shapes and sizes trying to work together under a single goal, with a single mindset, wouldn't it be better if they all had the opportunity to pick their own puzzle?
 * No matter what you do, the construction will keep collapsing from underneath you, symbolising both the futility of trying to make something for yourself in a communist hellhole and the inevitable collapse as the now downtrodden masses tear the old society down from the bottom up.