no major problems with it. as I've said for years, you can't effectively compress something like this into a two hour movie (running time: 2 hrs, 45 min., with a rumored 3 hour "ultimate" dvd release). mini series style is the way to go if you want a full, perfect adaptation.
it's as good as you'll likely get in this format. spoilage a comin.
I actually prefer the film ending to the comic, as Adrien's plan to frame Manhattan fits using him as the scapegoat much better than an alien squid (which Moore just lifted from an Outer Limits episode anyway). nobody else noticed the device was called "S.Q.U.I.D."? heh. as for the plausibility of the countries uniting, it's not that plausible either way, so why worry about it? it's a flaw of the story overall, not just this version.
