@Clean Cut Chaos the original game has the "shattering apart" death animation, as well as the "just fade away" animation for different enemies, so having some differentiation between the enemy death animations wouldn't be unprecedented.
I'd definitely appreciate the battle system differentiating between killing things that return to the lifestream from those that don't, because it's a good reminder to the player about the world, and sometimes interesting when learning about the enemies.
When it comes to things outside of common enemies who typically both appear and disappear inside the battle, I have to agree that the body dissipation thing shouldn't happen to them immediately. Aerith's death and funeral scene is a pretty important part of that. I've always thought that seeing the lifestream dissipation is a good representation of them being past the point of being revived (i.e. them passing on), but I also think that it's definitely been overused for things that aren't initially transubstantiated in form (like the Remnants in Advent Children).
Personally, I like the idea of seeing the Lifestream leave, and having their body remain behind any time we see someone die in the course of the game – especially because places like Gongaga and Corel Prison have graveyards, so we know that physical remains are a thing. Particularly, the deaths of the AVALANCHE crew are gonna be important, and I don't want them to feel ethereal. I want them to feel
painfully physical, while also giving the clear indication that they're not just missing a phoenix down.
That being said, I also don't think that it's the sort of game where having a Reactor full of the corpses of MPs you fight is important in selling the message about what you're doing, so clearing out the battlefield area of NPC-level random encounters is still fine for hyper-accelerated death processes vis-a-vis getting lifestream'd.
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