I'm translating an American article on a theatre production that is really challenging for a non-native speaker. Here's a passage describing one of the props, a car:
Indeed, the set, by Maria Tregubova, works its own defiant treachery: it’s made up of part trompe l’oeil deception, part functional props. Nowhere is its sleight-of-hand more beguiling than in a piecemeal car — only one door actually opens — into which [the actors] hop and circle the stage on a turntable track.
I can't understand what does the word "piecemeal" mean here. According to other articles on this production, the "car" is a giant photo of a car with a cut-out "window" through which one can see the actors' faces. There is no definition of "piecemeal" in the dictionaries that would be helpful here.
I also struggle to understand the meaning of the phrase "only one door actually opens": does the word "only" here mean "but" (like "you would think it this and that, but it's different, one door actually opens") or does it mean that "there are many doors, but none of them are working, except for this one"? Perhaps it would be clear if I understood the word "piecemeal".
Many thanks in advance, and I hope this is the last question I ask on this article : )