building the huge bunker near Voi in Halo 3, quote]
Well, they didn't BUILD the bunkder, they modified it by bringing in modern equipment. One of the marines when you're being escorted to the control room (or something like that, it's been a while since i played Halo 3.) that the bunker was make during one of the 20th century wars, (again, i'm not sure, I havn't played the game in a while). But it was something along those lines.
Now with everything else, i agree with you. I've often thought about writing a fanfic about how Johnson, 343 Guilty Spark, SpecOps Commander Half Jaw (Not his real name but it's my favorite nick name), and Miranda got their asses back to earth. IMO, it's one of the most annoying plot holes in the game as they NEVER mention EVER how they got the HELL back. As was how Johnson is still alive after the bajillion times he died in Halo 1. I know he was not a main character then, but still.