Before I go on, I feel obligated to warn readers that my discussion of Apollo 18 will contain spoilers.
So consider yourself warned.
Apollo 18 is a film in the mockumentary found footage style made famous by The Blair Witch Project and this results in a major inconsistency given that the premise of the film is that it purportedly documents the last manned mission to the moon and that no one survived this last mission; this begs the question as to how the footage being shown in Apollo 18 was exactly found since at the film's conclusion said footage is either in the abandoned Apollo lunar module on the moon's surface or mixed up somewhere in the tangled wreckage of the Apollo command/service module and the Soviet LK lander in orbit around the moon.
The Apollo command/service module in lunar orbit
Aside from the contradiction borne of its premise, Director Gonzalo López-Gallego's Apollo 18 suffers from the fact that screen-writer Brian Miller shows his hand wayyy too early, revealing to the audience almost immediately after the crew of the lunar module (“Nate” Walker and “Ben” Anderson, played by Lloyd Owen and Warren Christie, respectively) lands on the moon that the cause of all the mysterious happenings in the film are due to spider-like aliens disguised as moon rocks. In doing so, he missed a great opportunity to throw a couple of red herrings at the audience in the form of the cold war paranoia that was ostensibly the raison d'etre behind the mission of the Apollo 18. After all, shortly after their arrival on the moon and during the course of their top secret Department of Defense mission to deploy detectors designed to provide early warning of Soviet ICBM launches, Walker and Anderson stumble upon tracks which lead them to a Soviet lunar module.
The Soviet LK (Lunny Korabl - “lunar ship”) lander
The strange goings-on which follow, which include the US flag planted at their own landing site being tampered with and their lunar module being sabotaged, could have been attributed to a Soviet cosmonaut acting either on his own initiative or with official sanction, especially considering that the Soviet LK lander portrayed in the film, instead of being the cramped one-man spacecraft that it was in reality, looks big enough to accommodate at least two cosmonauts, something which Walker and Anderson fret about briefly after they discover the body of one cosmonaut before being assured by Houston that the Soviets sent only one man.
Schematic of the Soviet LK lander – you don't have to know how to read Cyrillic to see that this was strictly a spacecraft meant for one and noticeably less roomy than the Soviet lander portrayed in Apollo 18
Instead, we're shown “found footage” fairly early in the film which shows a moon rock moving around in the background and the only mystery in the film is what these moon rock spiders have against national flags since, during the course of the film, they not only mess with the US flag but there's evidence to suggest that they did some violence to the Soviet flag that was planted by the crewman of the LK lander. In addition to abusing flags regardless of the political systems they represent, these moon rock spiders also have the endearing habit of burrowing into human beings and turning them into batshit crazy pod people before ultimately killing them.
As you can probably tell, I was pretty disappointed by Apollo 18, especially since I really wanted to like this film. When I was a kid, I was very much into the US space program, and I'm probably dating myself by mentioning this, but when I was in this phase, the Space Shuttle had not yet made it into orbit, so for me, the US space program meant the Mercury, Gemini and Apollo spacecraft and Skylab, so when I found out about Apollo 18, I was pretty psyched.
The Apollo lunar module – one of the spacecraft that epitomized the US space program for me when I was growing up
My disappointment was rendered more acute because the film's shortcomings could have easily been remedied with some minor script doctoring. Given the credible performances of Lloyd Owen and Warren Christie (Ryan Robbins doesn't get to do much as command module pilot John Grey but he certainly acquits himself well given what he had to work with) and its great special effects, Apollo 18 could have been a good movie if only more attention had been paid to the script.
But I guess you could say that about every film cursed with mediocrity.