Headscratchers / Duke Nukem 3D

• In episode 3 there is a level that takes place on a movie set where they are making a movie about Duke's adventures in the previous 2 episodes. Considering the episode is supposed to take place only a few days at most after the last one, how would they have time to start making a movie about it?
  • Maybe it's the movie set Kubrick used to fake the moon landings?
• What exactly is the aliens' objective in their invasion? I get they're just there to be antagonists, but what are they doing besides that? They abduct women for reproduction, but it's never made clear what their reproductive cycle is. Never mind the fact that their forces seem to be composed of multiple different species; there's no way the assault aliens and the protector drones are the same race.
  • Official material like the manual and strategy guide reveal the answer: they're here to plunder Earth's resources. To make this a little easier, they first plan on firing a huge laser into the San Andreas fault, splitting the planet into smaller, more manageable chunks.