I already watched Kingsglaive once, months ago before the game's release. It just doesn't work as a standalone film but now that I've actually played the game past the first chapter, I actually understand where it fits in the overall story now and also it's place within it.
If I treat Kingsglaive as a roughly 2 hours long extended cutscene which fits between chapters 1 and 2, but which was obviously way too long to be stuffed into the game itself, it makes perfect sense.
The quality of CGI throughout Kingsglaive is absolutely exquisite too so it's hard to be mad at something that tries as hard as Kingsglaive does. Whatever failings it has, it's not because it's fundamentally a bad film. It's because it has to fit within the confines of a larger story yet also tell a complete story that attempts to be cohesive within the larger story. When this is taken into account, the many issues with the script seem much more forgivable.
Besides, that final sequence is pretty amazing. The obvious limits of the script and plot as glaring as they were, for the final set piece they pretty much were like fuck it, let's at least make this last fight sequence fucking ridiculous and awesome. It's like they combined Pacific Rim and Advent Children into one gigantic CGI orgasm.
