The sentence from the OP illustrates the use of a highly versatile and common syntactic construction, which in simple terms can be described as: Predicate + Main Clause. Here's another sentence illustrating this syntactic pattern:
"A long-time favorite of critics, Timothy Oliphant is set to win this
year's Oscar. "
The introductory noun phrase : "A long-time favorite of critics" ("A black comedy.." in the OP) is understood as predicated of the following NP "Timothy Oliphant". Or, to put it differently, the introductory NP has a clausal character. (if you wish, you can call it "I'll borrow the subject from the main clause" construction")
Now, here's the same sentence, with an added comma, representing a case of apposition:
"A long time favorite of critics, Timothy Oliphant, is set to win this
The intention here is quite different - we want to precisely specify the person/thing that is "a long time favorite of critics". Apposition, thus, is a term used for a concept/idea/construction with a far narrower meaning and use. We can predicate anything about anyone or anything, in any possible syntactic form, while apposition is a quite limited concept, both semantically and formally.
What strikes first from the sentences illustrating apposition is that the appositive pattern is fixed: "NP comma NP comma" - the appositive modifier is set off by commas (with the exception of two examples from CGEL illustrating detached appositive modifiers as a minor usage ) Not only that, the order is fixed too: anchor + appositive modifier. This sharply contrasts with the other construction explained here. The ascriptive NP from the first sentence is almost free-floating - we can move it around like: "Timothy Oliphant, a long-time favorite of critics, is set to win this year's Oscar" (again, this is not a case of apposition).
I found a thorough treatment of apposition in Quirk's "A Comprehensive Grammar of the English Language". I've read the part concerning what the authors termed "non-restrictive apposition", which is at issue here: ("supplementive apposition" in The Cambridge Grammar of the English Language). Here's what is said there:
Apposition is primarily and typically a relation between two noun
phrases...... In non-restrictive apposition the two NPs contribute
relatively independent information, with the first appositive acting
as the DEFINED expression, and the other appositive having a DEFINING
role ("the definer"). The defining role is reflected in the fact that
the second appositive is marked as parenthetic by punctuation or
Here's a useful clue : the template: "NP comma Main Clause" will never be understood as an apposition. The two adjacent NPs in this construction will never be read as "The Defined Expression + The Definer". As I said multiple times, these two NPs will be in a Subject+Predicate relation.
Another useful clue: the template: "NP comma, NP, comma" will typically, but not necessarily be an apposition. Only if the two NPs stand in the "The Defined - The Definer" relation will this construction be understood as a unique sort of a relation/construction that people termed "apposition". This example from CGEL nicely illustrates this point: "Kim Jones, a quite outstanding student, won a scholarship at MIT" . This is not a case of apposition - "a quite outstanding student" doesn't specify "Kim Jones", it "..expresses a property that is ascribed to Kim Jones". This is clearly set out in the definition provided in this grammar book: "The construction with a SPECIFYING NP as supplement is known as apposition".
As with any other syntactic construction, tons could be said about this one too. One less striking but very interesting aspect, for example, would be the use of pronouns as appositives. The appositive modifier is supposed to specify, but how can you specify something with a pronoun? "A black comedy, it, .. ". (Using "this", "that" etc. will similarly preclude this construction, e.g "this actor" instead of Timothy Oliphant in the second example above will make the sentence unreadable. Notice also that the anchor can be a pronoun: "We the supporters of.. ")
Apposition is all about being more specific about what the person has just referred to. I refer to X and then I refer to X again, only now in more specific terms. That's all there is to this construction. I believe there are good reasons for setting it apart from a superficially similar, but fundamentally different construction. We want to group similar ideas together, and to distinguish them from dissimilar ones. This is why I said earlier that we shouldn't label the NP from the OP sentence as apposition - it is not a minor terminological point.
It is not about one or the other term, it is about what these terms represent, and why they were introduced in the first place.