I loved the opening and thought that they did a really good job with that, and the very end was done well too. I also loved how intense and emotional the fighting was, allowing the characters to really shine.
However, (slight spoilers) I'm still skeptical in how a half-demon and a human destroyed a demon more powerful than the one that Inuyasha's father could only seal... The battle was very intense, and there were several times the situation seemed hopeless, which kept me on the edge of my seat, but, this being part of the show that it is, I knew that everything was going to end up alright. It was mostly a matter of HOW they were going to win.
Other than that, the movie was pretty good. Nothing special, but it wasn't bad, either. Mostly it just felt like a longer episode from the show.