P.T. feels like a loop. The entire experience plays out in an L-shaped length of corridor, a neat chunk of suburban home rendered impossible and Pac-Man-like by the fact that the door at the far end drops you back to the door at the start. You move through the space again and again, stuck deep within the machine. What's changing, and what stays the same? Are the walls growing dirtier? Is the art moving about when you aren't looking?