First-Person Tetris isn't, as you might think, a 3D version of Tetris viewed from a first-person perspective. Rather, it prioritises the perspective of each falling block so that, when you rotate, the block stays still and the entire well flips through ninety degrees. It's supremely disorienting.
I played long enough to clear one line before my head started spinning and I needed to lie down.
First-Person Tetris [site]