Putting this here simply to be informative in case someone searches for a similar answer. I saw some people asking if there were more levels to get the Earth rise achievement, because the game doesn't explicitly tell you what to do to get it, and doesn't tell you how to unlock the extra set of levels. The last mission of each campaign section is mandatory. It doesn't tell you this, but you have to listen to the audiotapes from the commanders, AND you have to do the Big Bust mission, in order to get the extra (and final) levels.

I don't know if anyone still plays this game, it seems pretty dead at this point, but I would've honestly never realized Big Bust is mandatory to get the new levels. I can't imagine how many people quit thinking the last level was the audiotape in section 3.