Why does it have to be a Proper Noun?

You should tell us more about what your game is about. As a sidenote, let me remind you that Kurt Cobain named one of its best success by asking his bassist for a song name, and the bassist replied "well, what is it about?" "its... about a girl" and the title became, "About a Girl". So ya, basically just find something simple that is unique to your gameplay.
If you wanna stick to the generic terms system, here's my call:

Survive the City

it has up to three hidden meanings, good luck deciphering them.