YSK if you've seen something traumatic, playing Tetris for a couple of hours afterwards can drastically reduce the chance of it becoming a deeprooted memory and causing PTSD
A single dose psychological intervention, which includes using the computer game Tetris, can prevent the unpleasant, intrusive memories that develop in some people after suffering a traumatic event.
Can confirm, not just with the game but similar activities eg: stacking those body parts into a nice cube really takes away from the stress of killing someone