I do think the ending hinges a lot on how much attention you've paid to details throughout the game and how many side tasks you pursued and completed. In this game, 90% of the tasks--even seemingly unrelated ones--inform or fold into the "main quest," and with a high-FYS build, you can stumble into the ending much sooner than is ideal.
Massive ending spoilers:
If you treat it solely as a whodunnit and don't engage with the broader political context and history of Revachol, including talking at length to, e.g., Rene and Joyce, the ending will lose a lot of its thematic heft. I think it also helps to have a broad political engagement in this world, in real life, to understand the currents that have or haven't shaped our society and moment. The revelation of the murderer will also seem more or less connected to everything depending on how much you've learned about Klaasje and Lely, and how many other minor clues you've discovered and talked about (the flowers on the rooftop, for instance, or Inland Empire/Shivers checks that concern the island). Another key element is your tolerance for a mystery being dispelled or transformed rather than solved. This isn't a pure detective story, and it doesn't "play by the rules"; the identity of the murderer is ultimately less important than the emotional significance of the murder--for H.D.B., for Martinaise and Revachol, and for the player. The game isn't about catching the bad guy who did the crime; it's about understanding that the past keeps crashing into our present and destroying us. That we can't escape it.
Likewise, if you don't engage as much as possible with Lena/Morell, talk extensively to Joyce, and exhaust every possible option at the church (learning as much as possible about the swallow/2mm hole, and ideally even speaking with Revachol via a major Shivers check), you lose a lot of the context around the phasmid and what it reveals. You may not even be able to communicate with it! In which case, yes, it will seem like "a weird insect showed up." I found myself almost tearing up in that moment because of what that phasmid had come to represent, and what it told me: that the pale was a human creation. What's happening to the world of Elysium, what's slowly choking it, is us. That's a resonant truth for our world, too.
Likewise, if you don't engage as much as possible with Lena/Morell, talk extensively to Joyce, and exhaust every possible option at the church (learning as much as possible about the swallow/2mm hole, and ideally even speaking with Revachol via a major Shivers check), you lose a lot of the context around the phasmid and what it reveals. You may not even be able to communicate with it! In which case, yes, it will seem like "a weird insect showed up." I found myself almost tearing up in that moment because of what that phasmid had come to represent, and what it told me: that the pale was a human creation. What's happening to the world of Elysium, what's slowly choking it, is us. That's a resonant truth for our world, too.
So yeah, best game.
