I was curious what the death/game over looks like, so I did a speedrun to kill all test subjects. It was worth it to see the crutches. :)
In case you weren't aware, I think there's a bug with how subjects are counted before buying any upgrades, since it showed all 4 with red X's in the top left when only one had died. Not a huge deal, it would only come up if someone tries to speedrun dying like I did
Anyway, here's what peak kill efficiency looks like:
