Almost everything that could be said about Goth is circumscribed by its era.
The novel that this film is based on was something of a minor sensation for how it captured and responded to the particular mood of that era—i.e. the early 2000s. Yet, even now that we're removed from that time, the novel retains a surprising number of more timeless qualities that recommend it. In other words, it holds up very well.
The situation with the movie adaptation is…
The first half is a blast. Its self-indulgence and its fanfiction-isms are exactly what gives the setting a lived-in feel that's been lost since the first movie. Unfortunately, those same tendencies turn into a slog in the second half. This approach to self-awareness turns depressingly tedious in a franchise whose identity is this contradictory. It's a shame, because if it held itself back and let the momentum from that first half carry through, it could've been one of the best in the series.
