Not much of an observation, but I couldn’t fit it on Twitter.  After seeing Batman Begins I wondered why there are no superheroes.  After playing Arkham City I know: no respawns.  In real life you’d just die.

All it takes is one moment of inattention, and it’d be worse if (as in Mirror’s Edge) a fall actually killed you. 

(Corollary: maybe we’d get superheroes if we had backups, as in some SF futures, e.g. Stross’s Glasshouse.  Though there’d be the annoying inconvenience that after a backup, unlike a respawn, you wouldn’t know what killed you.)