>>713605325 (OP)the city is your lifebar
this was done before in Superman Returns but here's the difference: THE ENEMIES DON'T KNOW THE CITY IS THE LIFEBAR
so they just won't ignore you to go attack a building
they will however take hostages, taunt with with hidden bombs, etc
you're bulletproof but rockets and grenades and shit can still knock you around, making it harder to fulfill objectives/protect people
halfway through the game you get hit with magic
your second, true lifebar appears because its the first time you've been hit with something that can actually hurt you