
It was never really clear to me what that was supposed to be. That is, until I watched this.
I'd heard that in the development of the Keen universe, Tom Hall took some inspiration from the old 1953 short film "Duck Dodgers in the 24th and a Half Century". So I watched it. You know, for nerd research.

Check out this little segment, starting just after the 5 minute mark.

https://www.dailymotion.com/video/x1ym9b7?start=314
The world makes so much more sense now.
I've previously tried to rationalise everything in the Keen games to fit into the "lore". To absurd levels sometimes. Including the whole "extra lives" situation.
To that end, what seems to be going on with that is those "cartoon deaths" where, although being horribly injured, you're still perfectly fine. I guess Keen just gets whacked right back to the start of the level or something.

It all makes sense. I am happy.