the aliens movies never made sense to me.
1) sleeper ships - don't be surprised when 100's or 1000's of years have gone by
2) surface mining ships -
a) that's not at all how mines work
b) there's nothing of value on the very top
c) there's nothing so valuable as to build a giant, interstellar, vtol strip mine so you can bring back a tiny, tiny, tiny amount of it. remember they are eating rocks right up until takeoff and not refining/extracting anything.
d) the only reason to have people on the ships is so something bad can happen to them.
3) the aliens defy conservation of anything. their incredible metabolism and perpetual drooling are fueled by "terror", and their reproductive methods are absurd.
4) why is everything made of steam and steel grates? not my first choices for spaceship materials.