In his book A Theory of Fun (now finally back in print), Raph Koster proposes a hypothetical modification of Tetris in which the blocks are replaced by human beings, Jews being dropped into a gas chamber by their Nazi imprisoners. In the book, the game is a thought experiment meant to illustrate the coupling between a game's abstract mechanics and its fiction or skin. I've elsewhere discussed this notion under the name "tight coupling."

As Raph notes today, a Brazilian team, inspired by the idea from the book has realized the game as Calabouço Tétrico. The result features a "generic" executioner rather than the image of a concentration camp, but the result is effectively disturbing, as it is intended to be. It might be the sound design that accomplishes much of that effect, but the entire result is worth seeing, not for enjoyment but as a way to understand better the way basic game mechanics can be altered by means of the contexts of their presentation.