This is amazing! Well, the game itself - a hobbled, ASCII-esque version of Tetris with only two block types - isn't amazing, but the fact that it comprises just 140 bytes is. 140 bytes in this instance also means 140 characters, so essentially this is a working game you could post on Twitter.
Play it in your browser here, then come back here and marvel that the below is all that's involved:
These people. They are clever people. I am not. I feel bad now.