However the aliens may not be carbon based.
Does not help. There are a lot of problems with life that is "not carbon based", and one of those problems that it shares with carbon based life, is the inability to live on the surface of the Moon (a very unfriendly environment, a near-total vacuum with horrendous temperature variations and little to no moisture).
Perhaps they feed on minerals or some as-of-yet unknown food.
Bad explanation, as "minerals" are generally very "tightly bound" chemicals, that do not really have any potential to extract chemical energy from (try eating a rock, try burning ash, etc). Lunar rocks are high in oxygen, but this oxygen is tightly bound to other elements- you have to
expend energy to release it.
Of course, abundance of volatiles is very low on the Moon too.
And even if they did somehow eat lunar regolith, how do they suddenly parasitise or infect creatures (humans) from Earth? Parasitism is a relationship that evolves over millions of years and requires a number of different variables to occur a certain way. If Sacculina parasites infect crabs but can't infect humans, how come moon-creatures can infect humans when there isn't anything remotely like a human for 300 000 kilometers?
I believe it was good if only to showcase the Apollo tech on the big screen.
Maybe, but the question is: is it a
good advertisement?
I would be inclined to say no. Even
Transformers 3 was better. It too spun the lunar conspiracy angle. There may be many reasons to hate Micheal Bay, but deep down he's probably pretty enthusiastic about the space program as well.
Anyone who actually believes it happened would already be conspiracy prone and therefore not worth argueing with.
Oh yes, let's establish a new "underclass" of those who are "conspiracy prone". :dry:
Seriously though, if it propagates conspiracy theories, it's a bad thing.
Also; I criticise
this a lot, but not some of the aspects of films like Avatar, because this ties itself into a specific situation by basing itself off of reality. A LK lander is more realistic than an ISV (the LK actually existed but the ISV would likely fry itself upon activating its propulsion system), but while the ISV can just wave its hands and suppose that someone figured out how to store antimatter in the next 150 years, it is
fact that the LK's dials and controls and soforth were labeled in Russian and it would likely be totally impossible for an untrained astronaut to pilot.
In short: a lot of works of fiction presuppose some things that allow that work of fiction to 'function' believably. Apollo 18 and similar works of fiction presuppose reality and don't obey it's rules, and are therefore
Whiny Plausibility Critic Bait.
If you enjoyed
Apollo 18, then that is good for you. It means your admission fee was not money wasted. But a lot of critics seem to have disliked this film, and from that I gather the conclusion that if it is (in the eye of the majority) a good film, it is only in the sense that it would be highly entertaining for my guests should I ever hold a "bad movie night".