It is a good concept, it fits well the last stand concept
I enjoyed playing it, I belieave the time to last stand bar was bugged because mine finished but it didnt do anything, but it is a good game :)
The time until Last stand bar isn't bugged: Its the time Until the Spaceships come. (the Last Stand against the aliens.) When the timebar finises you also get some extra health. But for both things I didn't have the time to make the visual feedback better so it happens almost unnoticed.
You Made a really cool game too!! :)