Moontrap is a star vehicle for a guy (Koenig) who was a supporting actor on the 60's Star Trek television series. It really seems like he might have had a hand in writing Moontrap (which is credited to the clearly fictitious "Tex Ragsdale"), as the insecurities of his character seem to be a reflection of how you would imagine Koenig himself might feel about his own career. His character frequently comments on how he should've let someone younger take this mission, and that he "blew it". But then, of course, he single handedly dispatches a half dozen killer moon robots and has space sex with a foxy moon alien. The truly outrageous part is how absolutely terrible Koenig's acting is. You are really forced to wonder if he has any human emotions at all to use as frame of reference. All this sounds like it would add up to some great cheesy movie watching, and it passes as that... pretty much. The goods (monsters, Bruce Campbell) are delivered far too infrequently in favor of boring and glaringly inaccurate NASA procedural scenes and clumsy, ineptly written dialogue scenes with the astronauts.
Note to Bruce Campbell completists; This movie, in terms of Bruce content, is probably not worth the effort it takes to find it. Campbell is present for much of the movie, but isn't given many lines. He does go pretty wild during his death scene but when he is resurrected in monsterized form, it only lasts for a few seconds.